The Alpha Helix

Space-filling model of the alpha helix.

[The Paulings in England: Part 5 of 5]

It has been said that sometimes blessings come in disguise, and so it may be that we have the damp English spring to thank for the elucidation of the alpha-helix structure of alpha-keratin – a fundamental and ubiquitous secondary structure pattern found in many proteins.

Linus Pauling was plagued by sinusitis for much of his time in England, and for three days in March 1948 it had become severe enough to put him in bed (as he was fond of saying over the years, this was before his vitamin C days). After a day spent devouring mystery novels, Pauling asked Ava Helen if she would bring him some paper and his slide rule, at which point he started trying to figure out how polypeptide chains might fold up into a satisfactory protein structure.

Pauling’s canvas was just an ordinary 8 1/2 by 11 inch sheet of paper. His first step was to draw the correct bond angles and distances onto the sheet, as determined from previous x-ray crystallographic work on polypeptides. Next he folded the sheet along parallel lines into a sort of squared-off tube. Doing so allowed him to add in representations of hydrogen bonds, which the impromptu model suggested would form between amino acid residues and, as a result, hold the turns of the polypeptide together.

The model made sense and pretty quickly it was clear that Pauling had discovered something important.  As he later wrote, his folded creation “turned out to be the structure of hair and horn and fingernail, and also present in myoglobin and hemoglobin and other globular proteins, a structure called the alpha-helix .”

Reconstruction of the alpha-helix paper model. Drawn and folded by Linus Pauling, 1982.

Pauling kept this idea to himself until his return to the United States because something didn’t match up quite right with the current laboratory data. Specifically, the turns of Pauling’s helix didn’t mirror the 5.1 angstrom repeat found in all of William T. Astbury‘s x-ray patterns. Pauling’s structure came close, but made a turn every 5.4 angstroms, or every 3.7 amino acid residues.

After his return home, with the assistance of colleagues Robert Corey and Herman Branson, Pauling continued refining his alpha helix structure and developing others, including the beta sheet. Simultaneously, the Caltech group’s chief British rivals at the Cavendish Laboratory published a paper titled “Polypeptide Chain Configurations in Crystalline Proteins.” The paper promised more than it delivered though, and while it listed many possible structures, Pauling found none of them to be likely. The competition was still on.

Pauling was finally convinced to publish when he received word that a British chemical firm called Courtaulds had created a synthetic polypeptide chain that showed no sign of Astbury’s 5.1 angstrom reflection in x-ray diffraction images. This was enough evidence for Pauling to decide that the 5.1 angstrom repeat was, perhaps, not a vital component of all polypeptide chains.  And so it was that in April 1951 Pauling, Corey and Branson published “The structure of proteins: Two hydrogen-bonded helical configurations of the polypeptide chain,” in the Proceedings of the National Academy of Sciences.

After devouring the Pauling group’s results shortly after their publication, Max Perutz headed to the Cavendish lab at Cambridge to check the data himself. Having confirmed the structure in images of horsehair, porcupine quill, synthetic polypeptides, hemoglobin and, for good measure, some old protein films that had been tucked away, Perutz wrote to Pauling, “The fulfillment of this prediction and, finally, the discovery of this reflection in hemoglobin has been the most thrilling discovery of my life.” He then published an analysis of his own data, concluding, “The spacing at which this reflexion appears excludes all models except the 3.7 residue helix of Pauling, Corey and Branson, with which it is in complete accord.”

Video Link: Pauling Recounts His Discovery of the Alpha Helix

It wasn’t until a year later that the mystery of Astbury’s 5.1 angstrom reflection was finally solved. In 1952, on a visit to the Cavendish, Pauling met Francis Crick, the then-graduate student who would go on to play a huge part in the discovery of the structure of DNA. The two maintained similar interests and during a taxi ride around Cambridge found themselves discussing the matter of the alpha helix. “Have you thought about the possibility,” Crick asked Pauling, “that alpha helixes are coiled around one another?” Whether Pauling had or had not considered this possibility remains a point of contention, but Pauling remembered replying that he had, because he had been considering a number of higher-level schemes for his helixes, including some which wound around each other.

Regardless, Pauling returned to Caltech and both he and Crick set to work on the problem. With help from Corey, Pauling discovered a means by which the alpha helixes could wrap around each other in a coiled-coil to produce the problematic 5.1 angstrom found in Astbury’s pictures of natural keratin.  Crick, in the meantime, was conducting a very similar study.  Pauling and Crick, independent of one another, ultimately submitted the solution to this puzzle for publication within days of each other, and at first there was a bit of grumbling as to whom the credit should be awarded. Though Crick’s note was published first, the Cavendish camp eventually conceded that Pauling’s paper included considerably more detail of consequence, and it was finally settled that both scientists had independently come to the same general conclusion.

Pauling receiving his honorary degree from the University of Paris, 1948.

After Pauling’s two fruitful terms as Eastman Professor at Oxford were up in July, the family split their remaining time between travels in Amsterdam, Switzerland and Paris. Pauling rounded off the trip by receiving yet another honorary degree from the University of Paris, and on August 25, 1948, the Paulings set sail once more on the Queen Mary.

His eight months in Europe had been productive and enlightening, but Pauling was ready to return to Pasadena where he could share the myriad ideas he had generated and gathered during his time away from Caltech. As we have seen, he was especially eager to get back to work on proteins, writing shortly before his departure that “I have continued to work on my theory of metals, and have been doing nothing about proteins. However, I am looking forward to being back home, and to thinking about that subject again.”


An Era of Discovery in Protein Structure

Linus and Ava Helen Pauling, Oxford, 1948.

[The Paulings in England: Part 4 of 5]

Though metals were consuming a good portion of his time during his fellowship at Oxford, Linus Pauling’s other projects never strayed far from his thoughts.  High on the list were the mysteries of proteins, whose structures and functions were slowly starting to be unraveled.

Pauling’s interest in proteins was spurred in the mid-1930s when the Rockefeller Foundation began to look most favorably upon the chemistry of life when deciding where their grant money would go. Early on, Pauling set out to tackle hemoglobin and though his affair with the molecule lasted for the remainder of life, Pauling certainly didn’t limit himself to the study of just one protein.

At a time when most were looking at proteins from the top down, trying to sort out the complicated data produced by an x-ray diffraction photograph of an entire protein, Pauling was working from the bottom up, in the process determining the structures of individual amino acids – the building blocks of proteins.

A specific protein that kept coming back into view over the years was keratin. In the 1930s, the English scientist William Astbury had studied the structure of wool, which along with hair, horn, and fingernail is made up primarily of this enigmatic protein, keratin. Astbury proposed that the structure was akin to a flat, kinked ribbon, but Pauling disagreed. “I knew that what Astbury had said wasn’t right,” Pauling recalled, “because our studies of simple molecules had given us enough knowledge about bond lengths and bond angles and hydrogen-bond formation to show that what he said wasn’t right. But I didn’t know what was right.” Pauling attempted to construct a model at the time, but could not match his structure to the measurements dictated by Astbury’s blurry x-ray diffraction images. Pauling wrote the project off as a failure and continued pursuing other interests.

In 1945 Pauling found himself seated next to Harvard medical Professor William B. Castle on a railroad journey from Denver to Chicago. Castle was a physician working on the nature of sickle cell anemia and the conversation that he shared with Pauling planted a seed in Pauling’s mind about the cause of this debilitating disease.

In the bodies of those suffering from sickle cell anemia, red blood cells assume a sickled shape when they are in the deoxygenated venous system but retain their normal flattened disk shape in the oxygen-rich arterial system. Noting this, Pauling suggested that perhaps the source of the problem could be a defect in the oxygen-carrying protein itself: hemoglobin.

Amidst his travels in Europe, Pauling continued to act on this idea as maestro from afar, directing the scientists in his Caltech laboratory to continue searching for differences in the hemoglobin of normal and sickled cells. In the meantime, he sought out and communicated new ideas gleaned from meetings such as the Barcroft Memorial Conference on Hemoglobin, held at Cambridge in June 1948. Pauling’s research team, in particular Harvey Itano and S. Jonathan Singer, were able to show experimentally that his hunch had been right, and less than a year after his return to Pasadena a paper was published that established sickle cell anemia as the first illness to be revealed as a truly molecular disease.

Linus and Peter Pauling at the model Bourton-on-the-water, England. 1948.

While in England, Pauling had occasion to interact closely with a number of scientific greats.  Among these were his close friend Dorothy Crowfoot Hodgkin, who is credited as a pioneer in the development of protein crystallography and was the winner of the 1964 Nobel Prize for Chemistry.  Likewise, Pauling conversed with Max Perutz, a protege of Sir William Lawrence Bragg‘s at the Cavendish Laboratory at Cambridge, who would go on to discover the structure of hemoglobin and receive the Nobel Prize for Chemistry in 1962.  While fruitful in many respects, these interactions served to increase Pauling’s feelings of urgency as concerned the race to determine the structure of proteins.

Bragg shared the 1915 Nobel Prize in Physics with his father for their early development of X-ray crystallography, and though there existed a long-standing scientific rivalry between Pauling’s and Bragg’s laboratories, it wasn’t until Pauling saw, with his own eyes, the work that was being done that he admitted he was “beginning to feel a bit uncomfortable about the English competition.” As he wrote to his colleague Edward Hughes back at Caltech

It has been a good experience for me to look over the x-ray laboratory at Cambridge. They have about five times as great an outfit as ours, that is, with facilities for taking nearly 30 x-ray pictures at the same time. I think that we should expand our x-ray lab without delay.

This realization prompted Pauling to get researchers in his lab started on work with insulin – an arduous and complicated process that required sample purification and crystallization prior to x-ray investigation. In relaying research findings from English scientists working on insulin to his partners back in Pasadena, Pauling intimated that

It is clear that there is already considerable progress made on the job of a complete structure determination of insulin. However, there is still a very great deal of work that remains to be done, and I do not think that it is assured that the British school will finish the job. I believe that this is the problem that we should begin to work on, with as much vigor as possible, under our insulin project.

Little did Pauling know that, while laying in bed, using little more than a piece of paper, a pen and a slide rule, he would soon make a major breakthrough in protein chemistry on his own.

New Insights into Metals and More

Linus and Peter Pauling at Warwick Castle, England. 1948.

[The Paulings in England: Part 3 of 5]

In his lab, a five minute walk from his office at Balliol College (where he was once caught boiling an egg on his electric space heater), Linus Pauling’s research took a turn from the contents of his lectures – intermolecular forces and biological specificity – and he found himself devoting his research time to metal theory. Pauling had planned to revise the index for his newly published freshman text, General Chemistry, during his Eastman Professorship, but couldn’t seem to get metals off his mind.  As he wrote in a letter to his Caltech colleague J. Holmes Sturdivant, “I thought that I would be doing work in connection with my freshman text while in England, but it has turned out that I have devoted all of my time, and presumably shall continue to do so, to work on the theory of metals and intermetallic compounds.”

He was aided in his lab by three other researchers – David Shoemaker, Hans Kuhn, and a young man from Holland, Dr. F. C. Romeyn. Pauling’s circumstances were proving to be highly productive, and in a March letter to Robert Corey, Pauling wrote of the impact that the change of setting was having in stimulating his thoughts:

I have been having wonderful success in my development of a theory of metals. I think that it has really been very much worthwhile for me to get away for this period of time, under circumstances favorable to my thinking over questions and trying to find their solution. The problem of metals has been on my mind for a number of years, and I haven’t been able to leave it alone, so it is a good thing that I have now managed to get it solved.

This new theory of metals was an extension of Pauling’s valence-bond approach to determining the structure of molecules, as initially developed in the late 1920s. Pauling was first exposed to quantum mechanics as an undergraduate at Oregon State University (then known as Oregon Agricultural College) and retained that interest as he transitioned to graduate studies and faculty employment at the California Institute of Technology.

In 1926 Pauling traveled on a Guggenheim Fellowship to study the developing field of quantum mechanics with physicists in Europe, and especially Germany. He brought these new ideas back to Caltech in the form of quantum chemistry, which he used to compute the electronic structures of molecules. This intuitive valence-bond approach was quickly judged a success and had been popular since the 1930s as a simple model for studying the electron dispersal in the bonds between molecules.

But all the while another chemist, Robert Mulliken (recipient of the 1966 Nobel Prize for Chemistry) had been steadily fostering a rival approach: the molecular orbital theory. While the Pauling family enjoyed springtime in Paris at the beginning of April, Pauling and Mulliken met head to head at a conference on Isotopic Exchange and Molecular Structure. There an entire day was devoted to the comparison of the two theories before a group of quantum chemists. Pauling had written earlier that molecular orbitals were confusing to students, but he learned at this meeting that one always has to stay one’s toes: with more mathematics under their belts, advanced chemistry students were increasingly hungry for the more quantitative approach that Mulliken’s theory offered.

Sometimes ideas come upon the great thinker at surprising times, and Pauling experienced just such a eureka moment during one of his twice-weekly Oxford lectures in February.  As he wrote to Holmes Sturdivant,

I have just had a great stroke of luck. While giving my lecture on Tuesday I suddenly realized that a calculation about resonance energy of metals that I had just made and was reporting contained the key to the strange valence numbers and numbers of atomic orbitals and unused orbitals that have turned up in my theory of valency of metals.

Notes on intermetallic compounds by Linus Pauling, March 1948.

Pauling worked out his ideas on electron theory and the structure of metals and intermetallic compounds through pages and pages of careful handwritten calculations. In looking at each manuscript now, Pauling presents a hypothesis about some aspect of metal theory and then proceeds to calculate, revise, and recalculate until the theory and the experimental x-ray diffraction data line up. For instance, on one day in March, Pauling was exploring intermetallic compounds from several different angles.  He writes “I shall now treat intermetallic compounds, with my new ideas – resonance of bonds when an extra orbital is available, importance of n=1/2, 1/4 etc., concentration of bonding electrons into strong bonds (Zn-Zn, etc as compared with Na-Na) , transfer of electrons with increase in valence.” Hybrid orbitals, bond lengths, and the overall stability of structures were other items on Pauling’s research agenda.

Of course, not every idea is a winner and a few theories led Pauling down the wrong path; in one manuscript Pauling set out to, as he wrote, “consider sp hybridization – how can we set up a secular equation to give the results given by my bond-strength postulate?”  In the end Pauling found that “the ratio does not come out as desired. It is evident that my assumption that the energies can be taken proportional to ‘bond strengths’ is not right.”  Missteps such as these didn’t deter Pauling from pressing on with his research, for as he often said, “The way to have good ideas is to have lots of ideas, and throw away the bad ones.”

Chemistry boasts its own special language, or nomenclature, and chemists like Pauling are to thank for the terms that make chemical jargon unique. As research advances, sometimes an entire new word is needed to describe an innovative concept. While tackling the nuances of metal theory at Oxford, Pauling wrote to Sturdivant about this very problem.

By the way, I think that we should do something toward improving the nomenclature. For example, coordination number is an awkward and unwieldy expression – we need one short, precise word for this concept. Perhaps ligancy could be used. It would fit in well with ligand and the verb to ligate. We also need some general words to express the bonds between one atom and the surrounding atoms – we now use the word bond to refer both to the electron pair bond that is resonating around among alternative positions and to the fraction of an electron pair bond that is a portion to a particular position. I have also felt troubled about using the word position in this way – to mean the region between two atoms. If we do introduce any change in nomenclature, it must be very well thought out, and must not involve too great a strain on the memory, or too great a departure from the past.

New fields also call for innovations in instrument development and research programs. Pauling was in constant communication with his colleagues back home about new tools that might be constructed to aid the researchers. He admired the Cavendish’s vast x-ray crystallography laboratory and also gained new insights from reading British journals devoted to scientific instrumentation. He would frequently send word back as to how Caltech workers could improve on a complex apparatus such as the specialized cameras for x-ray diffraction of metallic crystals.

Pauling was likewise intrigued by the English system of graduate education, wherein graduate students would take class work completely during the first year and then spend practically 100% of their time on research during the other two years. Pauling was always looking to improve upon existing programs, but as appealing as the English system was, he acknowledged that in implementing it one would run the risk of not knowing whether a student was an apt researcher for their entire first year!

A Royal Welcome

The Paulings at Magdalen Great Tower, Oxford. 1948.

[The Paulings in England: Part 2 of 5]

Arriving in Oxford right at the start of 1948, the Paulings had ample time to settle in before Linus Pauling’s first lecture on January 20th.  Shortly after unpacking, the family purchased bicycles for the whole group, and taken time “to peddle around the countryside.” The Paulings also explored their new surroundings in England via a “four-day automobile trip – to Cambridge, Peterborough, Nottingham, Manchester, Chester, Shrewsbury, and back to Oxford.”

By February, they had assimilated well into their new temporary home, and Pauling’s Oxford lectures were proving to be very popular – as he wrote to his Caltech colleague Carl Niemann: “My lectures have been going across well – there are 250 or 300 auditors still attending them.” A good start for what Pauling would later refer to as “one of the happiest years of my life.”

His regular schedule – two lectures on the nature of the chemical bond at 5:15 Tuesdays and Fridays, plus a weekly afternoon seminar in inorganic chemistry each Wednesday at 2:30 – sounds light, but Pauling certainly wasn’t taking it easy. On the contrary, Pauling was in high demand as a lecturer; not only were his Oxford lectures packed with standing room only, but he was also invited to speak all around England and Europe.  Everyone from the Istituto Chimico in Italy to the Gesellschaft Deutscher Chemiker in Hesse, Germany wanted to hear what this brilliant scientist and dynamic speaker had to divulge about their favorite field.

The clamor for Pauling was such that he was forced to turn many offers down, but still managed to give a mind-boggling thirty-nine lectures over six months, in addition to the three per week required by his Eastman Professorship.  As he wrote to his colleague Robert Corey, who was holding down the lab back in Pasadena,

I am continuing to get along very well – perhaps being kept a little too busy, with so many extra lectures to deliver. However, I feel that when there is so much interest in what I have to say it is proper that I make the effort to say it.

Among those who had the opportunity to hear him speak were attendees of many universities in England and Scotland, The Chemical Society, the British Undergraduate School of Medicine, as well as those who attended the three Scott Lectures for the Physics Department at Cambridge.  Pauling also gave three lectures at University College, London, the Sir Jesse Boot Lecture at Nottingham, a Bedson Lecture at Newcastle, The Liversidge Lecture for the Chemical Society and the first Lyell Lecture at Oxford.

In short, he was the toast of the town.  Priscilla Roth, Pauling’s secretary during his time at Oxford, wrote in a letter that Pauling was “getting a royal welcome everywhere he goes.”  And despite the Paulings’ initial disappointment in their lodgings, which kept the couple from entertaining their English friends to the extent they had originally hoped, the pair nonetheless found themselves swept up in a social whirlwind, attending an event almost every night – be it dinner, musical entertainment, or the ubiquitous English sherry party.

A prime example of this royal treatment was the reception afforded Pauling during his Friday Evening Lecture at the Royal Institution in London on February 27.   After a grand dinner, Pauling presented an hour long talk on “The Nature of Forces between Large Molecules of Biological Interest” to a glamorous audience of men in tuxedos and women draped in furs and jewels. Pauling biographer Thomas Hager described the evening as “an artifact from the days when the sciences were patronized like the arts … the scientific equivalent of playing Carnegie Hall.”

Trappings aside, the content of Pauling’s major lectures were ground-breaking.  As befitted his turn from structural chemistry to topics in molecular biology, his presentations typically brought to life new insight into the tiny world of molecules.

To begin, Pauling often posed the question, “what is it that defines living organisms as alive?”  He proposed that it is molecular architecture that makes creatures unique and imparts upon them the properties that we identify as life. Expounding on this thesis, Pauling would speak of the wonders of the giant molecules that comprise living organisms and their special biological roles.  In so doing, Pauling touched on the oxygen-carrying proteins hemoglobin and myoglobin as well as the mechanics of catalysis by enzymes.

Importantly, Pauling also remarked on the then-mysterious question of the genetic material – for this was in the years before the structure of DNA had been surmised by Watson and Crick. At the time, it was thought to be the “molecules of nucleoprotein” – instead of DNA itself – “that determine the characters of individual living organisms and that are involved in the transmission of these characters to their progeny.”

Pauling likewise questioned the boundaries of life by mentioning viruses: “Although these molecules may not ordinarily carry out the processes of respiration of air and metabolism of foodstuffs that we usually associate with life, they have one important property that causes us to regard them as living, the property of producing progeny.”  From there he brought the focus back to the triumph of the human body in discussing the operations of what he described as the biological “police force” of antibodies in identifying invaders, including viruses, and forming defenses against them.

After an exciting journey through the networks of biology and chemistry within the human body, Pauling often finished his lectures with a proposal that molecular architecture could be used to understand and attack degenerative diseases, such as heart disease and cancer, in the same way that penicillin and the sulpha drugs had so nearly eradicated infectious disease in the first half of the century.

Ava Helen Pauling at Stonehenge, 1948.

Though most of Pauling’s talks focused on scientific topics, he didn’t forget about the peace pledge that he had made on the Queen Mary. Indeed, as he traveled around England, Pauling was frequently able to make forays into the world of politics and peace in speeches such as the “The Third Party Movement in the United States,” presented to the English Speaking Union at Oxford University in March.

Somewhat radical in a time when Americans were fostering a mounting fear of communism and the Soviet Union, Pauling promoted a third party outside of the Republicans and Democrats called the Progressive Citizens of America, a group that identified itself as a “mild socialist organization” and supported George Wallace for President. Pauling’s speech painted for his British audience a portrait of the hysterical fears that were evolving into the Cold War. Socialism was lumped with communism in the minds of the American majority, and thus pressure from capitalists on the third party was very great – members and advocates of the movement were being questioned and losing their jobs.

Pauling was also critical of the Marshall Plan, which included $13 billion in U.S. aid for the European Recovery Program, and was worried about what would happen to industry in the hands of private owners now that there had been a “decision made that the Western European Union is to be capitalistic, patterned after past and present U.S., rather than socialistic, patterned after England.”  With the pressure building stateside on those deemed to have communist sympathies, it must have been a relief for outspoken Pauling to escape the tension, even if momentarily, prevailing in his home country.

The Paulings Go to England, 1947-1948

Crellin Pauling on the Queen Mary, 1948.

[Ed Note: Throughout 2011 the Pauling Blog will be featuring stories of the Paulings’ travels around the world.  This is part 1 of 5 in a series exploring the Paulings’ time in England, where they lived and worked for parts of two years after the close of World War II.]

The Second World War had come to a close and Linus Pauling was in transition from his war-time work back to the regular goings-on at the California Institute of Technology when he received an enticing invitation. Frank Aydelotte, American Secretary for the Rhodes Scholarship Trust and director of the Institute for Advanced Study in Princeton (academic home of such greats as Albert Einstein), wrote Pauling in January of 1946 proposing his appointment as the George Eastman Visiting Professor at the University of Oxford for the coming academic year.

The appointment would include a Professorial Fellowship at Balliol College – among the oldest of Oxford’s thirty-eight colleges. It was an attractive offer; with only two or three lectures a week required of him, Pauling would have ample time to visit other European universities and steep in the vibrant culture of international chemistry.

Pauling felt deeply honored by the invitation and was anxious to return to Europe once more after his last visit in 1930. But the appointment would have to wait a year while he remained in Pasadena to develop the chemistry and biology programs at CIT and finish his freshman text, General Chemistry, published in 1947. After much correspondence between Aydelotte and Pauling it was decided in early 1947 that he would serve as Eastman Professor for the winter and spring terms of 1948.

Though the professorship was postponed, Linus and Ava Helen managed to squeeze in a visit to England and Switzerland in June and July of 1947 for a mix of vacation and conferences. As was typical, the Paulings were kept busy with a multitude of social affairs. But after much hustle and bustle in Cambridge, where Pauling received an honorary Doctor of Science degree from the University of Cambridge, and Oxford, where he made preparations for his coming professorship, some quiet days in London and Stockholm were found, which the couple “devoted exclusively to resting and sight-seeing.”

Pauling receiving an honorary doctorate of science from the Earl of Athlone, University of London. July 1947.

Pauling’s role at the forefront of American chemistry (he would learn right before embarking on his voyage in December 1947 that he had been chosen as President-Elect of the American Chemical Society) also garnered him a key place in chemical matters abroad, and his July was filled to the brim with meetings and conferences. After three days at the International Congress of Experimental Cytology in Stockholm, he returned to England for the International Congress of Pure and Applied Chemistry. This event coincided with the International Union of Chemistry, where Pauling presided as Congress Lecturer, as well as the Centenary Celebration of The Chemical Society at the University of London.

At the latter event, Pauling received another honorary degree and delivered an after-dinner speech on behalf of his fellow honorary graduates.  In it, he called scientists to action and leadership in ending war and expressed hope that soon there would be a “supra-national world government, and that we shall all be fellow citizens, citizens of the world.”

Their two-month escape primed the Paulings’ excitement for their extended stay the coming year. However, the planning for the upcoming trip proved to be almost as difficult as the initial decision of when to go.

With England in the beginning stages of recovery from the war, travel in the UK was less than ideal. Securing a house for the five Paulings proved such a difficult task that the entire trip was on the verge of being canceled a month before departure. Ultimately the family decided to make the sacrifice of staying in a hotel – Linton Lodge – for several weeks until a small flat was finally procured for them.

The strict food rationing implemented in England during wartime carried over into the post-war years and presented a challenge for Ava Helen in preparing the very strict low protein diet necessary for keeping the effects of her husband’s nephritis at bay. Linus Pauling’s doctor, Thomas Addis, even wrote to The Ration Board to ensure that the visiting scientist would be able to receive the forty grams of protein (from eggs, milk, cheese, cereals, vegetables and fruits – not meat, chicken or fish) required by his unique 2,500-3,000 calorie diet.

Indeed, Pauling left no stone unturned in his planning, even writing to a doctor friend for advice on preventing seasickness. Despite initial skepticism that schools would be found for the children over in England, Ava Helen managed to enroll nine-year-old Crellin in the Dragon School – where he was the best man in his form – and fifteen-year-old Linda in the Oxford High School for girls, of which she maintained fond memories of the navy blue uniforms and fit in quite well, aside from her difficult Latin classes. Peter Pauling had just started his first term at Caltech, but was able to keep up with his studies overseas by studying independently with tutoring from an American Rhodes Scholar. Linus Pauling, Jr had just married Anita Oser – the great-granddaughter of John D. Rockefeller and Cyrus Hall McCormick – and the young couple remained in the States while the family embarked on their adventure.

Linus, Peter, Crellin, Linda and Ava Helen Pauling, 1947.

The excitement started for the Pauling children before they even boarded the Queen Mary and set sail for England on December 26.  During the holiday period, New York City was experiencing its worst snowstorm in years and it was the first time the three sunny California natives had seen the snow. Despite the marvels of the winter wonderland, the family really was stuck, and it was only by a stroke of luck (and some extra cash up front) that the Paulings were able to convince a taxi driver to push his way through to the docks and get them to their ship on time. They celebrated New Year’s Eve on the boat and in an interview Linda recalled that the members of the Canadian Ski Team, who were also on the same Atlantic voyage, were dancing with her all night – that is, until they found out that she was only 14!

Linus Pauling must have spent some time during the journey across the sea in introspective thought, for it was during this trip that he wrote his famous pledge, on the back of a piece of cardboard announcing one of his lectures: “I hereby make avowal that from this day henceforth I shall include mention of world peace in every lecture and address that I give.”  This pledge was just the first of many important moments in Pauling’s life that would occur as a result of his time in England.