Peter Pauling at Cambridge, 1953-1954

1954i.036-peter

Peter Pauling, 1954.

[The life of Peter Pauling, part 5 of 9]

In the first months of 1953, with his office mates scrambling to determine the molecular structure of DNA before his own father could beat them to it, Peter Pauling was mostly concerned with the English weather. He had been at Cambridge University since the fall of 1952 when he began his PhD program in physics at the university’s Cavendish Laboratory, and in that time he judged that he had seen a mere two full days of sun and was now officially fed up.

His father, by contrast, was mostly concerned with finishing his most recent edition of The Nature of the Chemical Bond, for which he had often solicited Peter as a source to provide example problems and solutions prior to his departure for England. As he was now beginning his graduate research, however, Peter was too busy to provide much assistance for this edition.

Instead, he was mostly occupying himself with a muscle camera developed by Hugh E. Huxley, a molecular biologist studying the physiology of muscle with Max Perutz’ Medical Research Council (MRC) Unit of Molecular Biology at Cambridge. Taking pictures of fibrous and globular proteins – beginning with insulin and tropomyosin – Peter applied the Cochran-Crick theory, with the goal of determining the helical structure of these protein molecules. This inquiry was, in principle, made possible by Linus Pauling’s work from less than a decade prior.

Since 1947, when the MRC unit was founded by Sir Lawrence Bragg, John Kendrew and Max Perutz had endeavored to use x-ray crystallography to determine the molecular structure of hemoglobin in sheep. By the time that Peter arrived at Cambridge, however, hemoglobin had proven to be an untenable object of study, and Kendrew’s focus had shifted to myoglobin. Whereas hemoglobin is found mostly in the blood, myoglobin is generally found only in muscle tissue. Both are proteins that carry oxygen to cells. Problematically, myoglobin is one fourth the size of hemoglobin, and too small for the era’s techniques of x-ray analysis.

To solve this issue, sperm whale myoglobin was used in hopes that the molecular details of the larger, oxygen-rich proteins of a diving mammal would be more observable with the tools then available. “Stranded whales are the property of the Queen,” Peter explained to his father as he discussed this work, “but we have an agreement with her to get a piece of meat if one comes ashore.” Nonetheless, though availed of samples from beached whales in the United Kingdom and from countries as far afield as Peru, Kendrew could not render the x-ray diffraction patterns with complete certainty.


 

myoglobin

Sperm whale myoglobin image created by John Kendrew.

In 1953, Perutz realized that by comparing the diffraction patterns of natural whale myoglobin crystals to crystals soaked in heavy metal solutions – a procedure called multiple isomorphous replacement – the positions of the atoms in myoglobin could be more accurately determined. Accordingly, Peter was tasked with making countless measurements in support of this effort.

Peter wrote to his father often over the next two years as he struggled to complete this project, which was the focus of his PhD. In particular, Peter asked for advice on how one might best get heavy metal atoms onto myoglobin, detailing his attempts to use everything from saltwater to telluric acid, which was used to produce salts rich in metallic contents, such as the element Tellurium.

Indeed, Peter’s work proceeded slowly, not least of all because of his knack for keeping things entertaining. Shortly after Watson and Crick’s discovery of DNA, for example, he fabricated a letter of invitation from his father, Linus Pauling, to Francis Crick, requesting Crick’s presence at an upcoming conference on proteins at Caltech. “Professor Corey and I want you to speak as much as possible during the meeting,” the impostor Pauling said to Crick in the fake letter, even urging him to consider lecturing at Caltech as a visiting professor. Linus Pauling had appeared to sign the letter himself, his signature skillfully forged. The letter proved so convincing that Crick actually replied, accepting the invitation to speak at the conference.

Before long, it became apparent that the entire communication was, in fact, a practical joke. Lawrence Bragg, the director of the Cavendish Laboratory, where Crick himself worked, was scheduled to speak at the proteins conference in the same time slot that the fake letter had proposed for Crick. Were it not for this, the deception might have gone even farther, since upon seeing his son’s forgery Linus himself was almost convinced that he had written the letter and had simply forgotten about it amidst the relentless pace of his schedule.

Ever a stickler for the details, however, Pauling noticed a grammatical error in the document that he would never have made. From there, he deduced the letter as having been authored by his mischievous son. For this transgression, Linus subtracted a five-pound fine from the $125.00 check that he sent to Peter each month.

The Arrival of Dan Campbell at Caltech

Dan Campbell, ca. 1940s.

Dan Campbell, ca. 1940s.

[Part 1 of 2]

As a scientist, Linus Pauling is remembered by many for combining his expertise in chemistry with other fields. Often times Pauling would start off thinking about a problem from a chemical perspective and end up learning about a field entirely new to him, like cellular biology or medicine. Though this sort of cross-disciplinary work is more commonplace today (partly because of the example that Pauling provided), in the 1930s it was fairly rare for scientists to combine different fields of study. This given, pioneers of the cross-disciplinary approach often found it difficult to identify like-minded researchers with whom to collaborate. Fortunately for Pauling, a man with a very wide network, other researchers often found him.

After delivering a talk about hemoglobin in 1936, Pauling was pleasantly surprised to be consulted by Austrian medical researcher Karl Landsteiner. For many years, Landsteiner had been trying to understand how antibodies in the immune system work, and he believed that Pauling’s knowledge of medicine and chemistry could help him in his investigations. An antibody is a disease-fighting macromolecule that targets and rids the body of unwanted foreign substances, such as viruses and incompatible blood types. Landsteiner wanted to know how antibodies can target specific foreign substances with such precision. This encounter drew Pauling’s attention to the field of immunology, which would eventually become an important part of his research and would remain so for many years to come.

Pauling’s communications with Landsteiner spurred an interest in looking into the chemistry of antibodies and their substrates, antigens. At the time, however, most of Pauling’s focus was necessarily occupied with finishing up his previous program of grant-funded research on protein structures. Furthermore, Pauling was not an immunologist and the demands on his time were such that he could do little more than keep immunology in the back of his mind.

It wasn’t until 1939 that Landsteiner once again brought Pauling’s full attention back to antigens when he used Pauling’s theory of protein structure in a discussion about antibodies. Reading Landsteiner’s article sparked several ideas for Pauling which quickly led to his drafting a rudimentary theory of antibody chemistry. Six months later he found the perfect opportunity to test some these ideas.


Image extracted from a glass plate display, “Pictures of Antibodies,” prepared for the First International Poliomyelitis Conference, New York, 1948. The caption accompanying this image reads: “…[An] antibody-antigen framework which may precipitate from a solution or be taken up by phagocytic cells.”


In January 1940, immunologist Dan Campbell first visited Caltech on a fellowship. Campbell was an Ohio native who had been trained at Wabash College in Indiana and George Washington University in St. Louis, before receiving a doctoral degree from the University of Chicago, where he was subsequently hired as an assistant professor. During his tenure at Chicago, Pauling invited Campbell to spend a fellowship period at Caltech.  Campbell was only scantly familiar with the Institute, but was aware of the reputation of its chemistry department and accepted Pauling’s offer largely on this basis.

Due to his unfamiliarity with the institution, by the time of his arrival in Pasadena Campbell had still not yet identified a research project on which to collaborate. Pauling advised Campbell to consider different researchers before making his final decision on where and with whom he might work. In the end, after asking around, Campbell chose to collaborate with Pauling on his theory of immunology.

This was a fortuitous decision, for several reasons.  First, in addition to immunology, Campbell had a background in biophysics and chemistry, which made him a perfect candidate to test and develop Pauling’s antigen theory. More importantly, as Campbell began his initial investigations, it became apparent that Pauling’s ideas were flawed and that Pauling’s knowledge of chemistry alone would not be sufficient to make further progress in immunological research.


Campbell and Pauling, 1943.

Pauling had alleged that antibodies were similar to denatured proteins; that is, a protein that has lost its secondary and tertiary structures and has unfolded into an amino acid chain. Pauling’s theory anticipated that antibodies were an unfinished protein that required specific antigens in order to fold into the proper secondary and tertiary structures.

According to this model, antibodies would only form hydrogen bonds and thus would coil around chemically complementary antigens. As such, the theory explained how antibodies are able to bind unambiguously to their complementary molecules. However, Campbell’s results did not support all of Pauling’s ideas. Though his research showed that antibodies were in fact proteins, their physical structure before and after binding to antigens remained unclear.

Pauling’s lack of evidence for his theory of antibody structure and composition limited him to publishing only a single theoretical paper in which he explained his ideas about antibodies. In July 1940 the Journal of the American Chemical Society featured Pauling’s “A Theory of the Structure and Process of Formation of Antibodies.” The article received much attention and, despite the lack of evidence, was widely acclaimed, though it failed to provide a definitive explanation for antibody structure.

After the publication of the piece, Campbell once again tested Pauling’s theory, and this time his results were much more confusing, to say the least. Initially, it appeared that Campbell had succeeded in creating artificial antibodies by simply denaturing beef globulins (a protein found in blood) and later allowing them to refold around an antigen.

Word of these results greatly excited Pauling, who began to envision the mass production of antibodies using Campbell’s method. Reality turned out to be not so simple; when students and postdoctoral fellows tried to replicate Campbell’s experiment, they were unable to obtain the same results. Looking back now, it seems most likely that Campbell’s research assistants had misinterpreted the results of his experiment.

Pauling knew that he would need more time with Campbell to refine his theory, but that could only happen if Campbell’s position at Caltech was secured. In 1942 Pauling arranged for the Institute to offer Campbell an assistant professorship, which he accepted. By 1950 Campbell had become a full professor.

Combining immunology and chemistry proved to be a commendable approach for tackling many health concerns of the time. Likewise, Campbell’s presence was crucial to the development of Caltech’s immunochemistry department, which over a span of five years grew from a single office (Campbell’s) to a space occupying most of the third floor of Caltech’s Church Laboratory. Students and professors alike flocked to the growing department to discuss questions and engage in research on immunology, using chemistry as the basis of their approach. From the outset, both Pauling and Campbell benefited from one another’s expertise while colleagues at Caltech, and their partnership would continue to yield fruit for many years.

Pauling and Perutz: The Later Years

[Concluding our series on Max Perutz, in commemoration of the Perutz centenary.]

In 1957, Max Perutz and Linus Pauling wrote to each other again on a topic that was new to their correspondence. This time Pauling asked Perutz to sign his petition to stop nuclear weapons tests, a request to which Perutz agreed.

Signature of Max Perutz added to the United Nations Bomb Test Petition, 1957.

Signature of Max Perutz added to the United Nations Bomb Test Petition, 1957.

As the decade moved forward, the discovery of the double helical structure of DNA attracted ever more attention to the work of James Watson and Francis Crick. In May 1958, Perutz asked Pauling to sign a certificate nominating his colleagues Crick and John Kendrew to the Royal Society. Pauling agreed, though stipulated that Kendrew’s name be placed first on the nomination, as he expected that Crick would get more support. As with Pauling’s bomb test petition a year earlier, Perutz agreed.

At the beginning of 1960, William Lawrence Bragg wrote to Pauling about nominating Perutz, along with Kendrew, for the 1961 Nobel Prize in Physics. Pauling was hesitant about the nomination, thinking it was still early, as their work on hemoglobin structure had only recently been published. Pauling also felt that Dorothy Hodgkin should be included for her work in protein crystallography. Bragg thought this a good idea and included Hodgkin in his nomination.

By March, Bragg’s nominations had gone through and Pauling was asked to supply his opinion. After spending some time thinking about the matter, Pauling wrote to the Nobel Committee that he thought that Robert B. Corey, who worked in Pauling’s lab, should be nominated along with Perutz and Kendrew for the Nobel Prize in Chemistry instead. Pauling felt that if Perutz and Kendrew were included in the award, Corey should be awarded half, with the other half being split between Perutz and Kendrew. Pauling also sent a letter to the Nobel Committee for Physics, indicating that he thought that Hodgkin, Perutz, and Kendrew should be nominated for the chemistry prize. Pauling sent a copy of this letter to Bragg as well.

Pauling’s letter to the Nobel Committee, March 15, 1960. pg. 1.

Pg. 2

In July, Bragg replied to Pauling that he was in a “quandary” about Corey, as he was “convinced that” Corey’s work “does not rank in the same category with that which Mrs. Hodgkin or Perutz and Kendrew have done.” Perutz and Kendrew’s efforts, he explained, had theoretical implications directly supporting Pauling’s own work, whereas Corey’s research was not that “different from other careful analyses of organic compounds.” Once everything was sorted out, Perutz and Kendrew were awarded the Nobel Prize for Chemistry in 1962 (the same year that Watson and Crick, along with Maurice Wilkins, won in Physiology/Medicine, and Pauling, though belated for a year, won the Nobel Peace Prize) and Hodgkin received the Nobel Prize for Chemistry in 1964. Robert Corey never was awarded a Nobel Prize.


Linus Pauling, Max Delbrück and Max Perutz at the American Chemical Society centennial meeting, New York. April 6, 1976.

Perutz and Pauling corresponded very little during the 1960s, with Perutz writing only to ask for Pauling’s signature, once for a photograph that would be displayed in his lab and a second time for a letter to Italian President Antonio Segri in support of scientists Domenico Marotta and Giordano Giacomello, who were under fire for suspected misuse of funds.

In 1971 Perutz read an interview with Pauling in the New Scientist which compelled him to engage Pauling on scientific questions once again. Perutz was surprised to have read that Pauling had tried to solve the structure of alpha keratin as early as 1937 and that his failure to do so led him to study amino acids. Perutz wrote that had he known this in 1950, he, Bragg and Kendrew might not have pursued their own inquiry into alpha keratin. Pauling responded that he thought his efforts had been well-known as he and Corey had made mention of them in several papers at the time. Pauling explained that he had difficulties with alpha keratin up until 1950, when he finally was able to show that the alpha helix best described its structure. Perutz replied that he was aware of Pauling and Corey’s work and the alpha helix, but was surprised that Pauling’s early failure to construct a model led him to a more systematic and fruitful line of research.

Perutz also wondered whether Pauling had seen his article in the previous New Scientist, which reflected on Pauling and Charles Coryell’s discovery of the effect of oxygenation on the magnetic qualities of hemoglobin. Perutz saw this as providing “the key to the understanding of the mechanism of haem-haem [heme-heme] interactions in haemoglobin.” Pauling responded that he had not seen Perutz’s article but would look for it, and also sent Perutz a 1951 paper on the topic. Perutz took it upon himself to send Pauling his own article from the New Scientist.

A few years later, in 1976, Perutz again headed to southern California to attend a celebration for Pauling’s 75th birthday, at which he nervously gave the after dinner speech to a gathering of 250 guests. Before going to the event in Santa Barbara, Perutz stopped in Riverside and visited the young university there, which impressed him. Perutz wrote to his family back in Cambridge that he wished that “Oxbridge college architects would come here to learn – but probably they wouldn’t notice the difference between their clumsy buildings and these graceful constructions.”

Perutz also visited the Paulings’ home outside Pasadena, which elicited more architectural comments. Perutz described to his family how the Pauling house was shaped like an amide group, “the wings being set at the exact angles of the chemical bonds that allowed him to predict the structure of the α-helix.” Perutz asked Pauling, perhaps tongue in cheek as he thought the design somewhat conceited, “why he missed the accompanying change in radius of the iron atom.” Pauling replied that he had not thought of it.

Bertrand Russell and Linus Pauling, London England. 1953.

In preparation for his speech, Perutz also took some time to read No More War! which he concluded was as relevant in 1976 as when it was first published in 1958. Perutz saw Pauling’s faith in human reason as reminiscent of Bertrand Russell’s. Indeed, the many similarities between the two were striking to Perutz, and he included many of them in his talk, “except for their common vanity which I discreetly omitted.” In a personal conversation, Perutz asked Pauling about his relationship with Russell which, as it turned out, was mostly concerned with their mutual actions against nuclear weapons. Perutz was somewhat disappointed that “they hardly touched upon the fundamental outlook which I believe they shared.”


Perutz and Pauling were again out of touch for several years until April 1987, when Pauling traveled to London to give a lecture at Imperial College as part of a centenary conference in honor of Erwin Schrödinger. Pauling’s contribution discussed his own work on antigen-antibody complexes during the 1930s and 1940s, during which he shared a drawing that he had made at the time. Perutz was in attendance and noticed how similar Pauling’s drawing was to then-recent models of the structure that had been borne out of contemporary x-ray crystallography. Perutz sent Pauling some slides so that he could judge the similarities for himself.

Flyer for Pauling's 90th birthday tribute, California Institute of Technology, February 28, 1991.

Flyer for Pauling’s 90th birthday tribute, California Institute of Technology, February 28, 1991.

The final time that Pauling and Perutz met in person was for Pauling’s ninetieth birthday celebration in 1991. Perutz, again, experienced stage fright as he gave his speech. But he was encouraged afterwards, especially after receiving a compliment from Francis Crick who, according to Perutz, was “not in the habit of paying compliments.” Perutz told his family that the nonagenarian Pauling “stole the show” by giving one speech at 9:00 AM on early work in crystallography and then another speech at 10:00 PM on his early years at Caltech. Perutz found it enviable that Pauling stood for both lectures and was still getting around very well, though he held on to the arm of those with whom he walked. Without coordinating, Perutz and Pauling also found a point of agreement in their talks, noting that current crystallographers were “so busy determining structures at the double” that they “have no time to think about them.” This rush often caused them to miss the most important aspects of the newly uncovered structures.

Just as Perutz first encountered Pauling through one of his books, The Nature of the Chemical Bond, so too would Pauling’s last encounter with Perutz be through a book, Perutz’s Is Science Necessary? Pauling received the volume in 1991 as a gift from his friends and colleagues Emile and Jane Zuckerkandl. Pauling’s limited marginalia reveal his interest in the text’s discussions of cancer and aging research. Aged 90 and facing his own cancer diagnosis, Pauling was particularly drawn to Perutz’s review of François Jacob’s The Possible and the Actual which sought, but did not find, a “death mechanism” in spawning salmon. Pauling likewise highlighted the book’s suggestion that “like other scientific fantasies…the Fountain of Youth probably does not belong to the world of the possible.” And Pauling made note of particular individuals that he had known well, like John D. Bernal and David Harker. Pauling deciphered the latter’s identity from Perutz’s less-than-favorable anonymous portrayal.

Pauling also noted spots where Perutz wrote about him. While most of these references were positive and focused on topics like Pauling’s influence on Watson and Crick and his breakthroughs on protein structure, one in particular was not. Perhaps less cryptic than the reference to Harker, Perutz described how “one great American chemist now believes that massive doses of vitamin C prolong the lives of cancer patients,” following it with “even more dangerous are physicians who believe in cancer cures.”

While critical, Perutz really meant the “great” in his comment and he continued to repeat it elsewhere. After Pauling passed away in August 1994, Perutz told his sister Lotte that “many feel that he [Pauling] was the greatest chemist of this century” while also being “instrumental in the protests that led to Kennedy and Macmillan’s conclusion of Atmospheric Test ban.”  He reiterated this idea in the paragraph that concluded his obituary of Pauling, published in the October 1994 issue of Structural Biology.

Pauling’s fundamental contributions to chemistry cover a tremendous range, and their influence on generations of young chemists was enormous.  In the years between 1930 and 1940 he helped to transform chemistry from a largely phenomenological subject to one based firmly on structure and quantum mechanical principles.  In later years the valence bond and resonance theories which formed the theoretical backbone of Paulings work were supplemented by R. S. Mullikens’ molecular orbital theory, which provided a deeper understanding of chemical bonding….Nevertheless resonance and hybridization have remained part of the everyday vocabulary of chemists and are still used, for example, to explain the planarity of the peptide bond.  Many of us regard Pauling as the greatest chemist of the century.

Pauling and Perutz in the Golden Age of Protein Research

Max Perutz, 1987. Image Credit: Graham Wood.

Max Perutz, 1987. Image Credit: Graham Wood.

[Part 3 of our series celebrating the Perutz centenary.]

In 1939 Max Perutz’s girlfriend gave him a book token for Christmas. Working on finishing his dissertation on the structure of hemoglobin, Perutz used that token to purchase Linus Pauling’s recently published text, The Nature of the Chemical Bond.

In the obituary of Pauling that he wrote some fifty-five years later, Perutz described how the “book transformed the chemical flatland of my earlier textbooks into a world of three-dimensional structures” and “fortified my belief, already inspired by J. D. Bernal, that knowledge of three-dimensional structure is all-important and that the functions of living cells will never be understood without knowing the structures of the large molecules composing them.”  The purchase of Pauling’s book marked the beginning of a long, fruitful and sometimes contentious correspondence between the two men, working on separate continents but united by similar interests.


Not until 1946 did Perutz first write to Pauling, asking for assistance as he labored through his research on the structure of hemoglobin. The Cavendish Laboratory, where Perutz was located, did not have the latest equipment that was available to Pauling at Caltech. In particular, Perutz needed a Hollerith punch-card machine to carry out calculations of the three-dimensional Patterson-Fourier synthesis. Perutz knew that Pauling’s lab was already conducting calculations of this sort and that the work Perutz was doing “would have to be done sooner or later, if the molecular structure of the proteins is to be worked out.”

As such, Perutz hoped that someone in Pauling’s lab might do the calculations for him. Pauling was not moved enough by Perutz’s request to offer the labor of his own team, replying that enlisting someone do such work in a “routine way” could lead to confusion. Pauling did offer that Perutz come to Pasadena, or send a surrogate to do the work, if he could find the money. Perutz was unable to support such an undertaking and so ended that conversation.

Linus Pauling and Lord Alexander R. Todd. Cambridge, England. 1948.

Two years later, in 1948, Pauling was in England, enjoying a stint as George Eastman Professor at Oxford. It was during this time that he and Perutz met for the first time in person. Perutz described his first experiences of Pauling’s lectures, in which

he would reel off the top of his head atomic radii, interatomic distances and bond energies with the gusto of an organist playing a Bach fugue; afterwards he would look around for applause, as I had seen Bertrand Russell do after quoting one of his eloquent metaphors.

The two also found time to talk together about their own particular research projects.

Pauling’s work at Oxford touched directly on Perutz’s own program, in what would become a oft-noted story in twentieth century history of science. As Pauling lay in bed with a cold, he did not stop working, choosing to spend his time making planar peptide models with paper chains. From his paper folding exercises, Pauling, according to Perutz’s obituary, “found a satisfactory structure by folding them into a helix with 3.6 residues per turn.” (A story that Pauling relayed many times himself.) The structure would come to be known as the alpha helix.

After Pauling recovered from his illness, Perutz showed him his own model of a polypeptide chain which was part of his larger hemoglobin model and was similar to fibers described by William Astbury. To Perutz’s “disappointment, Pauling made no comment,” and gave no hint as to his own breakthrough, which he announced the next year in a “dramatic lecture.”  That later unveiling of the alpha helix gave rise to a famous Perutz anecdote, which later informed the title of a book of essays that Perutz published.

When I saw the alpha-helix and saw what a beautiful, elegant structure it was, I was thunderstruck and was furious with myself for not having built this, but on the other hand, I wondered, was it really right?

So I cycled home for lunch and was so preoccupied with the turmoil in my mind that I didn’t respond to anything. Then I had an idea, so I cycled back to the lab. I realized that I had a horse hair in a drawer. I set it up on the X-ray camera and gave it a two hour exposure, then took the film to the dark room with my heart in my mouth, wondering what it showed, and when I developed it, there was the 1.5 angstrom reflection which I had predicted and which excluded all structures other than the alpha-helix.

So on Monday morning I stormed into my professor’s office, into [William Lawrence] Bragg’s office and showed him this, and Bragg said, ‘Whatever made you think of that?’ And I said, ‘Because I was so furious with myself for having missed that beautiful structure.’ To which Bragg replied coldly, ‘I wish I had made you angry earlier.’

 


Once Pauling returned to Pasadena, he and Perutz fell into a minor quarrel. In December 1950, Perutz had heard that Pauling had been “annoyed” by Perutz and John Murdoch Mitchison’s paper, “State of Hæmoglobin in Sickle-Cell Anæmia,” which had been published in Nature that October. Pauling was upset that Perutz and Mitchison had suggested that crystallization caused cells to sickle without properly citing his own seminal work on the subject.

In a December letter, Perutz said he was “very disappointed” that Pauling was upset with the publication, not only because there was a reference to Pauling, et al. in its introductory paragraph, but “particularly because all the new experimental evidence we report seemed to fit in so beautifully with the basic ideas set out in” Pauling’s co-authored Science article, “Sickle Cell Anemia, a Molecular Disease,” published in November 1949. Perutz explained his position in more detail, noting,

There is perhaps a slight difference between our points of view. Whereas you regard the sickling as being due to an aggregation and partial alignment of hæmoglobin molecules by a lock and key mechanism, an interlocking of specific groups in neighbouring molecules, we regard the cause of the sickling as being simply a crystallization, due to abnormally low solubility of the reduced hæmoglobin. No specific interaction of the kind you mention need be involved in the second process, though it obviously may be…I am sorry that this misunderstanding between us should have arisen, particularly as I have spent much effort trying to convert unbelievers to your scheme.

Pauling waited until the following February to respond and explained his feeling that readers of Perutz’s article might conclude that Perutz was making an original proposal. Having made this statement, Pauling, in his own way, moved beyond the quarrel by telling Perutz about his more recent work showing that “hemoglobin is not crystallized in the sickle cells, but is only converted to the nematic [or liquid crystal] state.” The ice broken, Perutz quickly responded by inviting Pauling to take part in informal discussions about protein structure at the Cavendish Laboratory before an annual conference, to be held in Stockholm. Pauling, however, could not attend.

The next year, Pauling attempted to visit England, this time to speak at a conference about the alpha helix, but was delayed due to his passport renewal being denied on account of his political activities. Perutz wrote that Pauling’s “absence had a sadly damping effect on our meeting at the Royal Society, and it made the discussion rather one sided as there was no none to answer the various objections to the α-helix raised by the Astburites and Courtlauld people” since Pauling’s supporters were unprepared to defend Pauling’s position without him. Perutz was also keen to show Pauling his own progress, an eagerness that Pauling reciprocated. By July Pauling had cleared up his passport problems and was able to spend time in person discussing his and Perutz’s work.


By 1953 Perutz and Pauling were quarrelling again over proper citation, though this time it was Perutz suggesting that Pauling had not given Francis Crick enough credit regarding the coiling of alpha helixes. Pauling explained to Perutz that, while he was at Cambridge the previous summer, he had talked with Crick and John Kendrew at length. During that conversation, according to Pauling,

There was only brief discussion of α keratin at this time, and, if my memory is correct, only a few sentences were said about the coiled coil, as Crick calls it. We discussed the fact that the 5.15-Å meridional reflection offers some difficulties of explanations, and that also there seemed to be a discrepancy in the density of α keratin. The discussion was very brief. Then Mr. Crick asked me if I had ever thought of the possibility that the α helixes were twisted about one another. I answered that I had. So far as I can remember, nothing more was said on this point.

Pauling went on to emphasize that “the idea was not a new one to me then” and that his own description of it in Nature was different from Crick’s understanding. Perutz ceded this point, adding that Pauling’s differences with Crick “stimulated Crick to clarify his own” ideas on the coiling of alpha helixes. More generally, Perutz found that the competition that arose between the two labs as they worked on similar problems helped to push each forward, thus leading to positive advances.

The famous group photo of the Pasadena Conference on the Structure of Proteins, September 1953. Pauling stands front row, third from left. Perutz stands two rows behind Pauling. [Image credit: The Archives, California Institute of Technology]

That September, Perutz made his first visit to California in order to deliver a paper at the Pasadena Conference on the Structure of Proteins, at which were gathered all of the world’s major figures in the field, including Jim Watson and Francis Crick, newly famous for their double helical structure of DNA. Perutz told his wife, Gisela, that his paper was “well received.” Additionally, with all of the different perspectives presented, there was “an atmosphere of soberness, and a realization that no-one’s solution of the protein problem was complete, and every approach was still fraught with complications.” Perutz was also quite taken with the Paulings’ home and their hospitality, pointing out that Ava Helen had invited him “after one of the meetings for a swim in their garden.”

Correspondence between Perutz and Pauling dipped a bit after the conference, though Pauling did take a moment to congratulate Perutz on being elected to the Royal Society the following Spring. While the exchange was brief, it reflected the long relationship built up between the two over the preceding years and, in particular, a confluence of work that had boosted the esteem of both scientists.

Perutz had begun looking at the structure of wool proteins back in 1951, thinking that there might be similarities to hemoglobin. He became excited after finding Pauling’s work on alpha helixes in fibers, thinking that the structure might be present in wool as well. His initial studies resulted in disappointment, but after adjusting the angle at which he was taking his x-rays by 30 degrees, he compiled new data that confirmed Pauling’s alpha helix structure. After applying it to his own work on hemoglobin, Perutz told Pauling “the discovery of this reflexion in haemoglobin has been the most thrilling discovery of my life…there is no doubt that it is a universal feature at least of all fibers of the α type. Whether all crystalline proteins show it remains to be seen.” Not suprisingly, Pauling was also “very pleased” with this discovery.

This research opened the door for Perutz to be considered by the Royal Society. But it was his development of a technique for determining a three-dimensional view of structures derived from x-ray crystallography that assured his election. He did this be attaching mercury atoms to hemoglobin, which allowed him to figure out where the crest and trough of a given x-ray was in relation to the structure that appeared on the photos. Perutz later said that after he finished the work and published it in Nature at the end of 1959, he went skiing in the Alps, and by the time he returned he was famous, assuring his fellowship in the Royal Society.

Dr. Pauling’s Chiral Aliens

[A guest post expanding on Pauling’s idea for a science fiction novel. Post authored by the blog’s East Coast Bureau Chief, Dr. John LeavittNerac, Inc., Tolland, CT.]

Pauling lecturing with the "fish model" (foreground) that he used to demonstrate chirality, ca. 1960s.

Pauling lecturing with the “fish model” (foreground) that he used to demonstrate chirality, ca. 1960s.

In basic chemistry we have something called “chirality” which refers to a molecule with two possible non-superimposable configurations. One way to picture this is to look at your hands and place one on top of the other (not palm to palm) – your left and right hands are essentially the same shape but their shape is reversed. At the molecular level we can use one of the main building blocks of all proteins and all life – the amino acid alanine, depicted in the image below – to examine handedness.

alanine enantiomers

The diagram shows the arrangement of atoms of two alanine molecules, both of which exist in nature, arranged so that they are mirror images. They are the same molecules but if you turn the one on the right around so that it is facing in the same direction as the one on the left, the R (a single carbon atom in alanine with three bonded hydrogen atoms) on this alanine molecule faces toward the palm of the hand and the COOH moiety (a carboxyl group) and the NH2 moiety (an amino group) face outward away from the palm.

No matter how you rotate the alanine on the right, you can’t get the three moieties attached to the central carbon to line up in the same position as the alanine on the left. Likewise, you can’t get those hands to super-impose each other no matter how much you twist and turn them. So the alanine on the left is called L-alanine (levo- for the direction the molecule rotates photons) and the alanine on the right is called D-alanine (dextro- for the direction the molecule rotates photons). They are called “enantiomers,” or chiral forms, of alanine, and both exist in nature with identical chemical properties except for the way that they rotate polarized light.

There are twenty natural amino acids comprising the building blocks of all proteins. Of these twenty, only glycine is symmetrical around a central carbon atom and therefore glycine has no enantiomers. The other nineteen can exist in the L- and D-conformation.

Funny thing though, only the L-enantiomer is used to make proteins by the protein synthetic machinery of all life-forms, from single-cell organisms up to humans. It’s quite easy to understand why one enantiomer is used in life over random use of either enantiomer. In explaining this, note the pictures below, which show the three-dimensional globular structure of human beta-actin on the left and, on the right, the architectural arrangement of this actin in the cytoplasm of a cell.

actin

The protein composed of 374 amino acids has an intricate folding pattern with coils which would not be possible if both amino acid enantiomers for the nineteen amino acids were randomly incorporated into the protein. This three-dimensional structure has to be preserved in order for actin to perform its dynamic architectural function inside living cells, as shown in the picture on the right. The coils are possible because the amino acids are all L-amino acids and glycine is neutral; otherwise the protein would behave like a wet noodle. The precise structure of the actin protein determines its function, which has been preserved and conserved since the beginning of all eukaryotic life-forms (that is, cells with a cytoplasm and a nucleus). Understanding the atomic forces that fold proteins in a unique shape is part of the reason why Linus Pauling received the Nobel Prize for Chemistry in 1954.


Aside from those who closely follow this blog, it is not well known that Linus Pauling was an avid reader of science fiction. In a 1992 interview with biographer Thomas Hager, he described his motivation to write a science fiction novel. The story line was to be the discovery of a human-like race from another planet that had evolved to use only D-amino acids (D-humans) rather than the L-isoform (L-humans). He explained that he never got around to writing this novel because the real science he was doing took all of his time.

If our L-humans met up with those D-humans, what consequences would there be? Well, what we would see in D-humans are people virtually indistinguishable from ourselves – barring, of course, the possibility that these extraterrestrials evolved out of some unearthly environmental niche. However, no mating, blood, or tissue sharing would be possible between these two races.

To explain this, consider the experience you have had when you accidently put your hand in the wrong glove. As you know, this doesn’t work well. All protein interactions and reactions catalyzed by enzymes require a direct fit to work. Substrates of enzymes have to fit precisely into the catalytic active site of the enzyme, like your hand fitting into the correct glove. Since L-humans have a different chirality from D-humans, nothing would fit or be transferrable, because of asymmetric incompatibility between L- and D- macromolecules. Even the food on our planet would not likely be nutritious for D-humans because all living things on Earth are L-organisms. In D-lifeforms, the actin coils would coil in the opposite direction and the DNA double helix would have to spiral in the opposite direction as well; otherwise the analogous D-proteins would not bind or fit on the chromosomal DNA.

scifi-051970

It seems reasonable that D-humans might be found on other planets if you consider how life got started. By a quirk of nature on Earth, L-amino acids got a head start and self-assembled into peptides (small proteins) when this essential process for life as we know it got started. The assembly of only one enantiomer isoform into a peptide may have been favored thermodynamically over co-random assembly of L- and D-isoforms. This essential process evolved into a well-organized, membrane-protected and energy-driven protein synthetic machinery in single cell organisms like bacteria. Today, humans have essentially the same protein synthetic machinery that evolved in primordial bacteria and all life-forms on Earth have the same genetic code.

There are two essential enzymes that work together to catalyze protein synthesis in all living cells. One enzyme, called aminocacyl-tRNA synthetase, binds the amino acid to a transfer RNA molecule (there is one of these enzymes and a specific tRNA for each of the twenty amino acids). The second enzyme, peptidyl transferase, catalyzes the formation of a peptide bond linking two amino acids at the start of a chain and does this over and over again until the full length protein is synthesized and folded into its functional conformation. These two essential enzymes do not recognize the D-isoforms of the nineteen asymmetric amino acids. Thus, our chiral L-specificity has been preserved since the beginning of life.

I can’t think of any reason why the D-amino acids would not support life, but it has to be one isoform or the other, not both. Apparently Pauling felt the same way. Should it ever come to pass, D-humans will be interesting to meet and they will be equally interested to meet us, hopefully without mutual disappointment.

The Continuing Voyages of the R/V Alpha Helix

Schematic of the R/V Alpha Helix, 1966.

Schematic of the R/V Alpha Helix, 1966.

[Part 2 of 2]

Built in 1965, the R/V Alpha Helix, named after the protein structure discovered by Linus Pauling, had proven itself – over the course of two years and two voyages totaling 34,110 miles – to be a versatile research vessel. The National Science Foundation (NSF), which owned and had sponsored the construction of the vessel, was pleased with the ship’s performance in the Pacific Ocean and in the Amazon River. So in early February 1968, they deployed her on her third voyage, this time to the Bering Sea.

Due to environmental hazards posed by the Bering Sea, the expedition there was smaller in time, distance traveled, cost and crew. The voyage lasted nine months, cost $574,000 ($3.8 million in 2013) and utilized fifty scientists from five nations. The mission’s typically eclectic goals were to study how animals survive in frigid environments; to determine why spawning salmon suffer from atherosclerosis; and to investigate the feasibility of building research labs on floating sea ice. The Alpha Helix performed admirably, though she lacked sufficient hull strength and engine power to safely break through all of the ice that she encountered and thus required escorting by the U.S.S. Northwind, a U.S. Navy icebreaker. Researchers from the University of Alaska, Fairbanks (UAF) reported on the vessel’s performance to their school, a report which heavily influenced the future design of the Alaska Region Research Vessel.

In the years that followed, the Alpha Helix continued to be sent on missions as often as was safe. She averaged one mission a year, each taking between nine and thirteen months. In 1969 she went on a $613,000 ($3.85 million in 2013) expedition to New Guinea to study mammals, birds, fishes, bioluminescence and heatless light produced by fireflies, fungi, and fish. The U.S., Australia, New Guinea, Indonesia, Malaysia, France, and Japan sent 66 researchers on the trip. The years 1970-1971 saw the Alpha Helix undertake a 25,000 mile expedition to the Galapagos Islands, Antarctica, and the Marshall Islands. In 1972 she went to the Solomon Islands, West Hebrides and the Western Caroline Islands.

After her 1972 mission, she was sent to dry-dock for retrofits and routine maintenance. The retrofits mostly involved upgrading her lab equipment to the most modern gear, work which required an appreciable investment of time. Not until mid-June 1976 did she launch on another voyage (See 3-14-14 update below) – a second trip to the Amazon River basin. This trip was more extensive than the first: it lasted a full year and required sailing upriver all the way to the headwaters of the Amazon, 2,500 miles inland. One hundred and twenty scientists from the U.S., Brazil, Columbia, Peru, Canada, Italy, Scotland, England, West Germany, Denmark, Norway, Chile, and Switzerland studied a diverse range of topics including the genetic structure of “primitive man” amongst Brazilian Indian groups; hemoglobin in fish and their ability to see; chemical characteristics of the Amazon River; the ability of certain Amazon fish to live on land; the resistance of various organisms to stress; and the toxic and medicinal properties of local flora. The expedition was extremely productive and also extremely hard on the vessel, which upon return to the U.S. was put in dry-dock again for about three more years.

In 1980 UAF sent a message to the NSF requesting a larger, more modern research vessel to replace their aging and cramped ship (only 80′ long), the R/V Acona. The NSF decided to replace the Acona with the Alpha Helix, and transferred her from Scripps Maritime to UAF. Upon arrival, she was immediately put into dry-dock again, where she underwent extensive retrofits. The focus of her labs was changed from mostly biological research to general oceanographic studies. And the ship’s equipment was modernized: the vessel received a strengthened hull for icebreaking, more cold-weather protection was added, and deep-sea oceanographic winches were installed below decks. All of these retrofits brought the Alpha Helix up to American Bureau of Shipping classification standards for a ship of her size.

1966s.4-bw

The Alpha Helix remained busy and valuable in the employ of UAF.  One particular task of note was to provide “systematic description of the Alaska Coastal Current from British Columbia to where it empties into the Bering Sea at Unimak Pass.” This data was invaluable in predicting the path of the oil spill emanating from the Exxon Valdez disaster in 1989. She also spent extensive amounts of time studying wildlife and water in the Bering Sea, Arctic and Alaska regions. During one trip taken in the early 1990s, she traveled about 25,000 miles, slightly more than the circumference of the Earth. Despite this, UAF increasingly came to feel that the Alpha Helix was insufficient for their needs. Specifically, they felt that her size was a limiting factor and that the hull was not strong enough to carry out the heavy ice work that they required.

In 2004 UAF put the Alpha Helix in dry-dock indefinitely and thus concluded a period of great productivity. Between 1981-2004, the ship had averaged 151 sailing days per year, and logged 3,629 total days doing research. Of those, she spent 2,390 days (65.8%) in the Bering Sea and Arctic Ocean, 907 days (25%) in the Gulf of Alaska, 187 days (5.2%) in southern Alaskan waters, and 145 days (4%) in other locations. The massive amount of research that she facilitated was mostly funded by the NSF, which paid for 76.4% of the cost. The National Oceanic and Atmospheric Administration (NOAA) covered the second highest amount at 10.8%. The remaining 12.8% of her operational costs were funded by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the Bureau of Ocean Energy Minerals Management Services (MMS), the Office of Naval Research (ONR), private sponsors, the North Pacific Marine Research Program (NPMRP), NASA, UAF, and the Alaskan state government.


The Alpha Helix was kept in dry-dock from 2004-2007, at which point she was sold by UAF to Stabbert Maritime, a family-run private company with a fleet of about 10 vessels. At the time of this writing, the company was owned by Mr. Daniel Stabbert. In a phone interview conducted in 2013, Stabbert spoke of his affection for the vessel.  He described her as “the SUV of the fleet…you could beat the [heck] out of her and she’d just keep running.” She is very fuel efficient, and the company gave her a bulbous bow to further increase fuel efficiency. They put on speed stabilizers and stern jet thrusters to further increase her stability in rough seas; they also removed one of the smaller machine shops and expanded the science team quarters and the lounge, so it can now carry a science staff of 21.

Between 2007-2010, the Alpha Helix was contracted by Stabbert Maritime for missions in the Bering Sea, Alaskan waters and the Arctic Ocean. She worked for various groups, mostly doing research on geology, fisheries and drill site surveys for Shell Co. and other oil companies. During this time, she was also contracted by the U.S. Navy to monitor noise levels on nuclear submarines undergoing degassing and repair operations; other contracts she performed for the Navy remain classified. In late 2010 she was sent to the Gulf of Mexico to assist with the cleanup required by the Deepwater Horizon oil spill. She remained in the area for a year to help monitor local fisheries. In 2012 the Alpha Helix was sent to Trinidad to conduct hydroscopic research and collect core samples.

Over the past few years, government research for funding has been decreasing, which makes running research vessels riskier for private companies. As such, Stabbert decided that he needed to upgrade his fleet to more multipurpose vessels, which the Alpha Helix most definitely is not. Therefore, despite his personal affinity for her, Mr. Stabbert sold the Alpha Helix to the University of Mexico City (UNAM) and it is now uncertain what the future holds for the ship. No matter what, the vessel has made regular contributions to science over past 48 years, and has affected the lives of hundreds of people who worked on or with it, often in ways that were unexpected: in our interview, Stabbert reported that he had been on a trip to Thailand during the 2012-2013 winter season, and had run into a banker whose father was one of the researchers on the second Amazon expedition.

The Alpha Helix has proven to be a rugged, fascinating, and incredibly useful vessel that has brought together generations of scientists from around the globe to collaborate in finding out how this amazing planet works. In furthering our understanding of the world around us, she has acted in a spirit that surely would have pleased Linus Pauling.

Update (2-12-14):

We were tickled to receive this message and photo today from JC Leñero of the CICESE research center, Ensenada, Mexico:

You may like to know that last year, we purchased the R/V Alpha Helix from the guys at Stabbert Maritime, in order to replace our smaller Research Vessel, the Francisco de Ulloa (28 meters LOA). As of today, Alpha Helix keeps her name (and, regarding the historical weight of bearing said name, we will not rename her), has her home port at Ensenada, Mexico, she flies the Mexican flag and is due to begin research operations again, hopefully in a few months, after some maintenance to her machinery is completed.

bo-alpha-helix

The B/O Alpha Helix, 2014.

Update (3-14-14):

A further update submitted by Tom Forhan, a former marine technician on the Alpha Helix.

Enjoyed reading about Dr. Pauling and the Alpha Helix, which I had never heard before. For the record, though, the ship did not waste any time between the refit in 1972 and the second Amazon expedition in 1976. Off the top of my head in 1973 it worked in both Baja California and then headed for research in Hawaii. The following year began a Pacific tour. After a stop in Australia, including work on bioluminescence around the Banda Sea in Indonesia, and an investigation of sea snakes in the Philippines. Heading back to North America the ship did research on salmon physiology in British Columbia, and in late 1975 or early 1976 headed down to the coast of Peru to participate in a multi-ship (including OSU’s research vessel) investigation in a program called CUEA, looking at El Nino. I believe OSU archives has some pictures of the Helix at sea during that time. After CUEA, the ship went through the canal and up the Amazon. My source here is my memory;I was a marine technician aboard the ship during those years.

The R/V Alpha Helix

The R/V Alpha Helix, 1966.

[Part 1 of 2]

It was early 1966 when Linus Pauling received a letter informing him that a new research vessel had just been constructed in Washington state. The reason this was notable to Pauling was the vessel’s name – it was called the R/V Alpha Helix, named after a secondary structure of proteins that Pauling had discovered.

The Alpha Helix was designed by L.R. Glosten and Associates, a naval architecture firm based in Seattle, Washington. It was built by the J.M. Martinac Shipbuilding Corporation in nearby Tacoma; construction began on September 9, 1964, and the keel was laid on December 9, 1964. The Alpha Helix is 133’ long, 31’ abeam, 14.5’ deep, and made with welded steel construction, transversely framed. She is powered by an 820-horsepower General Motors diesel engine, which drives a variable pitch propeller (for superior speed control) at 800 rpm and provides a top speed of 12.25 knots and a cruising speed of 11 knots. She carries a 29,250 gallon fuel tank, which at 9.5 knots gives her a range of 6,500 miles. The Alpha Helix also holds a second tank which contains 5,000 gallons of potable water.

She is a pure research vessel, and designed to be extremely compact and versatile; she has air-conditioning for tropical conditions and a reinforced hull strengthened for “moderate ice work” in arctic seas. On the port, aft side of the vessel, she has a cargo crane capable of lifting up to 5,310 lbs., which she needs, as in the hold she carries a jeep and a prefabricated 8×12′ shore laboratory. The Alpha Helix is also outfitted with mountings such that special work platforms can be fixed to the hull just above the waterline, running from bow to stern. She carries two skiffs and two workboats, measuring 17′ and 24′ long, respectively.

Despite her relatively small size, the Alpha Helix is designed to use space at maximum efficiency. At the time of her construction, she had space for a crew of 12 and a scientific party of 10. Additionally, she has ample room for research, including a library “with a large blackboard and acoustics suitable for conferences and chamber music.” But the heart of the vessel are her numerous research laboratories. She has a wet lab taking up 81 square feet, which at the time of construction could be chilled to 5° C. She also featured 457 square feet of dry labs, electrophysiological labs, optical labs, and a freeze lab that could be chilled to -20° C. These spaces required a significant quantity of specialized equipment which would be difficult to replace or repair during voyages, so she also has a full machine shop, equipped with lathes, drills, presses, welding equipment, and even a glass-blowing station. At the time of construction in late 1964, the Alpha Helix cost $1,272,021, roughly equivalent to $9.14 million in modern currency.


Invitation to the dedication of the R/V Alpha Helix, June 1966.

Invitation to the launching of the R/V Alpha Helix, June 1965.

The Alpha Helix was launched on June 29, 1965 in Tacoma, after which point she set out for San Diego, California. She was owned and had been funded in near entirety by the National Science Foundation (NSF), which had assigned her to work from the Scripps Institute of Oceanography, operated by UC San Diego.

The vessel was going to be dedicated at a large ceremony on March 11, 1966. At the same ceremony, the new Scripps Marine Facility and the R/V Thomas Washington were also slated for dedication. Dr. P.F. Scholander, a professor of Physiology and the director of Scripps’ Physiological Research Laboratory, wrote to Pauling and asked him to serve as the principal speaker at the event, due in no small part to the name of the Alpha Helix. Pauling wanted very badly to attend but was unable to do so as March 11 was the day that he was scheduled to be in New York City to begin his ill-fated libel lawsuit against The National Review, which had published two editorials that accused Pauling of being a communist, a “megaphone for Soviet policy…” and a traitor. Due to Pauling’s inability to attend, Prof. Scholander invited Dr. Robert W. Morse to be the principal speaker. Morse was a Navy veteran of World War II, the assistant secretary of the Navy for research and development, and the chairman of the Committee on Oceanography of the Federal Council for Science and Technology.

Shortly after the dedication, the Alpha Helix embarked upon its maiden voyage, an eight-month, 16,500 mile expedition named “Expedition Billabong” (an Australian term for a waterhole). James Faughn captained the vessel for the mission, which would extend to Australia’s Great Barrier Reef, with brief stops at the Cook Islands, American Samoa, and Hawaii upon the return to southern California. The entire mission was funded by the NSF, and its objectives were to study desalination of seawater by mangroves, electrophysiology of mollusks, symbiotic interactions in corals, and osmotic and cardiovascular behavior in dugong. During the course of the expedition, 44 scientists from 19 different institutions sailed on the Alpha Helix. Pauling wanted to serve as a researcher on the initial trip, but his lawsuit prevented it. Of the scientists on board, 22 hailed from the United States, while the remaining 20 came from Australia, New Zealand, England, Sweden, and Japan. The vessel performed her mission admirably and no modifications were made after the voyage.

After a few months of routine maintenance, the Alpha Helix departed in early February 1967, for her second voyage. This expedition lasted 11 months, and the destination was far up the Amazon River, deep into the jungle. The NSF sponsored this trip as well, which cost $600,000 (about $4.14 million in modern dollars). The Amazon trip was grander than the first voyage; the total distance traveled was 17,610 miles. And the time, distance, and cost of the trip were not the only increases: 82 researchers from the U.S., Brazil, England, Canada, Norway, West Germany, France, New Zealand, Sweden, Australia, Japan and the Soviet Union participated as well. The mission’s research goals were ambitious and exotic in equal measure. They included:

  • “the insect-free Rio Negro River”
  • singing habits of cicada
  • hallucinogenic snuff used by indigenous locals
  • sloths, electric eels, piranha and fresh-water dolphins
  • infrared sensing capabilities of the boa constrictor
  • the physiology of salt and water in animals
  • the potential of crude petroleum emanating from “smog” given off by certain jungle trees
  • respiratory mechanisms in indigenous fruits
  • the moisture secreting capabilities of trees
  • sap pressure in the “drowned forests of Brazil”
  • the metabolism of fish
  • respiration of Galapagos Island marine iguanas

Once again the expedition was a solid success and the Alpha Helix performed admirably. In fact, the mission ended up being more even informative than the scientists had originally anticipated, as on the way to the Amazon they discovered ten new species of deep-sea scorpion fish.

Very quickly the Alpha Helix had proven herself to be an excellent, compact and flexible research vessel. While the first two voyages had taken place in tropic climates, the NSF next had plans to try out her arctic capabilities. As 1968 began, crews loaded the vessel up for her next trip, to the Bering Sea and beyond.