A quick glance at the “Today in Linus Pauling” widget found at the top of the left sidebar of the Pauling Blog gives an excellent representation of the span and influence of Linus Pauling’s career. Rarely does a day go by where he didn’t write at least one manuscript or give a speech at a university or some other institution. Most days, readers will also note that he won some sort of award – including, of course, his two Nobel Prizes in chemistry and peace. Basically, Pauling’s career fits very well with the old cliché that anything can be done if the mind is simply set on it.
However, if one looks closely enough, a few failures can still be picked out of Pauling’s illustrious career. One of these failures is undoubtedly his attempt at determining the correct primary structure of DNA. Pauling first started working with DNA in the early 1950s, right around the time when his scientific career was reaching its peak. During this time, Pauling’s pursuits had also taken a controversial political shift – work which caused him to be denied a passport for a short period of time. This passport denial, because it is believed by many to be the reason why Pauling was beaten to the structure of DNA, is the topic of today’s post.
Near the end of 1951, Pauling received an invitation to attend a meeting of the Royal Society in England; a meeting that was specially designed for him to address questions about his protein structures. The meeting was scheduled for May 1, 1952, and promised to give Pauling an opportunity to visit King’s College in London, where he knew Maurice Wilkins had some excellent X-ray patterns of DNA.
However, when Pauling sent in his passport renewal application in January 1952, he was upset but unsurprised to find it denied by Ruth B. Shipley, the head of the State Department’s passport division. Shipley didn’t give Pauling a good reason for the denial, stating only that “the Department is of the opinion that your proposed travel would not be in the best interests of the United States.” Reading between the lines, Pauling’s liberal views had clearly earned him the label of “possible Communist,” and Shipley, who was a fervent anti-Communist, had the authority to deny passports at her discretion.
Fortunately for Pauling, the delay caused by the situation was not a long one. In the summer of 1952, he sent in another passport application. Again, Shipley immediately denied it, but her decision was overruled – after much deliberation – by higher-level employees of the State Department. Eventually, Pauling was notified that he would be granted a limited passport to travel for a short period of time in England and France if he agreed to sign an affidavit stating that he wasn’t a Communist. Surprised and pleased by the news, Pauling immediately agreed and received his new passport within days.
Thus equipped with the necessary papers, Pauling traveled to England, where he stayed for a month. He visited the same places and talked with the same people that he would have earlier in the year, but he did not visit King’s College to view Wilkins’ X-ray data. As it turns out, Pauling wasn’t even thinking about DNA during his time in England.
After England, Pauling traveled to France, where he learned of the results of the Hershey-Chase blender experiment: DNA was in fact the site of the gene, not proteins, as Pauling had believed. Upon learning of the keen importance of DNA, he decided that he would solve the structure of the molecule.
However, when he returned to Caltech in September of 1952, he continued to work almost exclusively with proteins. It wasn’t until November that Pauling would finally take a serious stab at the structure of DNA. And, as has been well-documented, even with his excellent knowledge of structural chemistry, Pauling’s data – presented in the form of blurry X-ray patterns created by William T. Astbury – was insufficient. He ended up creating a model that was nearly identical to one Watson and Crick had made over a year earlier. Of course, Pauling soon learned that his structure was incorrect, and before he could make another attempt, Watson and Crick had solved DNA.
The importance of Pauling’s passport imbroglio is, as it turns out, counter to the popular mythology of the DNA story. Although the denial of Pauling’s passport caused minor delays in his travels, it surely did not keep him from determining the structure of DNA. Even if he had traveled to England as originally planned, it is unlikely that he would have visited Wilkins to view his X-ray data. Pauling, even after finding out that DNA was extremely important, made no effort to obtain better data, nor did he even work specifically with DNA for quite some time. One is forced to conclude then, that the reason that Linus Pauling was not able to solve DNA is that he never really put his mind to the matter, not because of a pesky passport denial that delayed his travels a mere ten weeks.
For more information on Linus Pauling’s DNA pursuits, please visit the website Linus Pauling and the Race for DNA: A Documentary History. For other information on Pauling, check out the Linus Pauling Online portal.