Force of Nature- The Life of Linus Pauling

by Thomas Hager

  The first paper was just a prelude. It was as though the alpha and gamma helixes, once published and out of the way, cleared his mind for all the other protein structures he had been thinking about. Everything began falling into place, and he spent March finishing more protein papers with Corey. "I am having a hard time keeping my feet on the ground now," Pauling wrote a former student in the middle of March. "I have been working night and day, neglecting almost everything else." It was the most exhilarating scientific work he had done since the early days of the chemical bond twenty years before. And he surprised even himself with what he produced.

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  In early April, Pauling and Corey sent the PNAS one of the most extraordinary sets of papers in the history of twentieth-century science. There were seven altogether, and they appeared dramatically as a unified group that dominated the journal's May issue. There was a detailed description of the pleated sheet. There was a new model for feather rachis, which they proposed was a mixture of pleated sheets and helixes. There were new ideas about the structures of synthetic polypeptides, globular proteins, and muscle. Most exciting of all for Pauling was what he called "an astounding structure" for collagen, a major protein in tendon. In collagen, he believed, three helixes were twisted around each other to form a single cable.

  Every protein researcher in the world immediately recognized the magnitude of Pauling's work. The proposed structures were complete and extraordinarily detailed; in a field where nothing like this had ever appeared, suddenly everything had appeared: It was as though a single composer had debuted seven symphonies on the same day.

  In Britain, Bragg read the papers, became almost apoplectic, and rushed to the Cambridge chemistry office of Alexander Todd, the eminent organic chemist and an old friend of Pauling's. Todd had never before seen Sir Lawrence in that part of the university and immediately took note of the physicist's red face and the papers—Pauling's— that he clutched in one hand. "I said it was nice to see him in chemistry and asked what had led to this unexpected visit," Todd remembered. Bragg, "in a somewhat agitated state of mind," demanded to know how anyone could make a decision between Pauling's spirals and the ones Bragg’s group had proposed earlier. Todd, who had already seen Pauling's manuscript, said he would certainly pick Pauling's because of its planar peptide bond. When Bragg said the bond could not be planar, Todd explained to him about resonance structures and double-bond character. "If you had checked with me before, I'd certainly have told you so," he said. Nonplussed, Bragg returned to the physics department.

  "I judge that he did not read The Nature of the Chemical Bond carefully enough," Pauling crowed when Todd related the anecdote.

  Perutz devoured all the Pauling-Corey papers in a single Saturday morning and set off for his laboratory. If the Caltech crew was correct and there were 3.7 amino acids in every turn of the alpha helix, then each individual amino acid along the chain should account for about 1.5 angstroms of the spiral's length. This amino-acid repeat distance in the protein's backbone should show up on x-ray pictures, but the 1.5-angstrom distance was so small that it would take special experiments to look for it. It was worth it, however, because of all the many structures proposed for alpha keratin only Pauling's spiral would create this particular spot; it would act as a sort of fingerprint for the alpha helix. Perutz placed a horsehair in his x-ray apparatus, curved a piece of film around it in a way that would catch the expected reflections, and shot it. He scanned the film as soon as it was developed. There it was: a fuzzy spot out on the far margins of the photo, a reflection that indicated a structural repeat every 1.5 angstroms. Perutz x-rayed a porcupine quill and found the reflection again, and again in synthetic polypeptides and hemoglobin. He even found it on the far margins of years-old x-ray pictures of proteins, where it had been ignored. Perutz, an unusually unselfish researcher, a man almost as happy to confirm the work of others as he was to make his own discoveries, wrote 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 his confirmatory findings, 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." In tandem with the Pasadena group's other data, he wrote, "it leaves little doubt about their structure being right."

  With that proof from his own shop, Bragg admitted by June that the alpha helix appeared to have some validity—although it still did not explain why natural keratin gave the 5.1-angstrom reflection—and congratulated Pauling on his "broadside" of protein papers, especially the one on the alpha helix. It was gratifying to Pauling when his old competitor wrote: "I do congratulate you most warmly on what I feel is a very real and vital advance toward the understanding of proteins." The parts of the broadside beyond the alpha helix were, however, not as settled, and the English protein community started the laborious process of dissecting Pauling's other papers, one by one.

  Erroneous and Vicious

  Pauling's protein-structure research took so much time in the first half of 1951 that he devoted relatively little time to political work. That did not matter, however, to those ferreting out Reds in public life. Thanks to the sharing of information between the FBI, the Tenney Committee, and HUAC, Pauling was now among the select group of prominent Americans at the top of every investigating committee's list of suspected Communists. Anytime mention needed to be made of Red subversion of the sciences or the peace movement, Pauling was there to point to, and fingers were leveled regularly during 1951. The anticommunist newsletter Alert spent three issues informing readers about Pauling's appearance before the California education subcommittee, with a copious listing of his front activities.

  Then on April 1, the day after Pauling and Corey sent in their seven protein papers for publication, HUAC named Pauling one of the foremost Americans involved in a "Campaign to Disarm and Defeat the United States" through his participation in a phony "Communist Peace Offensive." There was nothing new in the charges— the evidence was the already-public list of the left-wing groups and causes he had joined—but the invective reached new heights. "His whole record . . . indicates that Dr. Linus Pauling is primarily engrossed in placing his scientific attainments at the service of a host of organizations which have in common their complete subservience to the Communist Party of the USA, and the Soviet Union," HUAC's press release read. "Professor Pauling has not deviated a hair's breadth from this pattern of loyalty to Communist causes since 1946." Pauling responded by telling reporters, "I have associated myself in a smaller or larger way with every peace movement that has come to my attention. I shall continue to act in the way that my conscience tells me is best."

  A few days after the accusations made front-page news, Pauling opened a letter from the president of Marshall College in West Virginia noting his regret at having to withdraw an invitation to Pauling to address scientists in the area. The problem, the president wrote, was not, of course, Pauling's political beliefs but the possibility of "vigorous protests" by local citizens and the resulting potential embarrassment for Pauling and his wife. Pauling did not buy it. "I am disgusted that you should have acted in this way," he wrote back. But his suggestion that he be reinvited received no reply.

  Even more unconscionable from Pauling's point of view were the actions of the regents of the University of Hawaii. He had been scheduled to dedicate a new chemistry building on campus, but the regents—alerted by state antisubversive officials who had received a copy of Pauling's Tenney Committee file from their helpful California counterparts—forced the chemistry department to withdraw the invitation. Pauling learned about it from a reporter and again was blunt in his response: "I am very surprised that the regents of a university, who are supposed to be men of enlightenment and principle, would put a man on trial and publicly announce his conviction without having told him of the charges or given him an opportunity to refute them." When the controversy hit the papers
and the media came to DuBridge for comment, the president kept his distance, saying only that he could not see that the issue had anything to do with Caltech.

  Left on his own, Pauling wrote the Hawaiian regents of his "deep indignation" at their action. "Do you think that an American who insists on making up his own mind, who objects to being told what to do, to being pushed around by officious officials, is thereby made unAmerican?" he wrote. "I do not. I think that he is being more American than people who do not object." He enclosed a copy of his statement of political beliefs—including his denial of membership in the Communist Party—asked to be reinvited, and hinted at legal repercussions if he was not. The regents stood firm.

  Pauling decided to go the islands anyway. It was a good time for a vacation. His protein papers had just appeared in print, the political heat was being turned up, and he was ready for a rest. Going to Hawaii was also a good way to demonstrate his disdain for intolerance. "I thought that it would be worthwhile to go to Honolulu and to give some scientific talks, just to make it clear to the people of the Islands just how big a mistake the Board of Regents of the University of Hawaii made in withdrawing their invitation to me," he wrote a friend. He convinced the Hawaiian chapter of the American Chemical Society to invite him for a series of talks and flew to Honolulu with Ava Helen at the end of May. It turned out to be a delightful break. Wherever he spoke, he was greeted by enthusiastic groups of scientists eager to hear about his newest discoveries. Many shook his hand afterward and thanked him for his courage in speaking out against intolerance. The Honolulu newspaper took Pauling's side and began to question the regents' actions.

  It gave Pauling hope. For a brief moment it seemed that by standing up for his beliefs, he was not only preserving his reputation but giving heart to others.

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  A few weeks after his return, however, the atmosphere again darkened. Pauling had managed since 1948 to avoid any projects that would bring him back under the scrutiny of the loyalty program, but it was becoming more difficult. In 1951, with the Korean War in full flame and the Rosenberg trial refocusing attention on the question of atomic spies, Truman signed another executive order expanding his loyalty standards so that mere doubt of loyalty, rather than hard evidence, became the standard for dismissing government employees. Hundreds of cases were reopened, including Edward Condon's. This time the long-suffering physicist had had enough and quit his post as head of the National Bureau of Standards.

  With the expansion of government funding for science, especially classified defense research, enormous numbers of scientists, technicians, and engineers found themselves required to go through the mechanism of the loyalty program in order to find work. Originally, the military had overseen loyalty reviews and hearings, but now, faced with a new influx of civilian cases, the system had been revamped to provide more nonmilitary input. Behind the window dressing, however, the loyalty program still amounted to a shadow legal system. Nonmilitary scientists applying for work on classified government contracts would have their security files reviewed by the area commanding general. Questionable activities or associations would send the subjects' files to a regional personnel security board. The board had the power to revoke clearance—discharging the subject from any classified project—without ever seeing the person or presenting evidence. The only recourse for blacklisted scientists was to appeal to the Industrial Employment Review Board (IERB), where for the first time they were offered the chance to present their cases in person, with counsel. IERB hearings were a bit like Kafka rewriting Alice in Wonderland—hearings structured like trials, held outside the legal system, after a verdict had already been passed, with military men judging the political activities of civilians—yet at least they offered the chance for face-to-face questioning and cross-examination and lawyers. After the IERB passed judgment, there was nowhere else to go. The decision of the panel was final.

  Tens of thousands of researchers were caught in this topsy-turvy mechanism. Once denied clearance for any reason—and the reason could be as simple as joining a suspect group—they found it difficult to get employment anywhere, whether on a government project or not. The loyalty program did not turn up any atomic spies, but it had the practical effect of silencing dissent. Working in a way similar to the blacklisting techniques that had whipped the film industry into line, the loyalty oath/IERB system worked to prevent researchers from straying politically.

  Then Pauling himself was sucked into the loyalty program.

  Although he steered clear of classified defense work, Pauling served on the Caltech faculty committee on contracts, a position that required him to review the classified grant requests of others. The Air Force requested that everyone who looked at its contracts, even in a review capacity, be cleared to look at classified materials at a low level, one sufficient to see "confidential" or "restricted" materials as opposed to the higher-level "secret" or "top secret" documents. This type of lower-level clearance was routinely rubber-stamped; it rarely involved the type of full review that brought people before the IERB. In early 1951, Caltech sent Pauling's name, along with a number of trustees and faculty, for low-level clearance. All of them were granted without a problem—except Pauling's.

  In late July he received a letter from the local military security board notifying him that a request for access to classified material at Caltech was being denied. According to "information" in the board's possession, "you have been a member of the Communist Party and a close associate of Communist Party members . . . you have also been affiliated with or a member of numerous organizations which espouse Communist Party ideologies and on many occasions you have openly defended known Communists and Communist ideologies."

  Pauling immediately appealed the decision to the IERB. A hearing was set for November.

  - - -

  Ironically, at the same time he was being denounced in America as a Communist, news reached Caltech that Pauling was being denounced by Soviet chemists for his "reactionary, bourgeois" chemical ideas, especially his use of idealized resonance structures with no real independent existence. The Lysenko-era Russian researchers, intent on boosting the reputation of Russian achievements in structural chemistry, had for two years been tearing away at Pauling's "erroneous and vicious" resonance-based theories, which were seen as antimaterialistic and hence anti-Soviet. The chemists' division of the Soviet Academy of Sciences in the summer of 1951 formally resolved that Pauling's approach was "pseudo-scientific" and "idealistic" and should be rejected. Pravda trumpeted the decision, which was echoed in Soviet scientific publications with appropriate denunciations of Pauling's approach to chemistry as "contrived, a made-up convenience, an economy of thought that bore no relation to reality." A contemporary observer wrote in The American Journal of Chemical Education, "The intensity and crudeness of this invective appear to be without parallel in the annals of chemistry." Soviet chemistry would henceforth be anti-Pauling.

  It was a bizarre position to be in, reviled simultaneously by Americans for being a Communist and by Soviets for being idealistic. Privately, Pauling was "deeply concerned" about the Russian invective, writing a friend, "I have not been able to gain any understanding whatever of the meaning or cause for such an attack." Publicly, it provided a damage-control opportunity eagerly pounced upon by Lee DuBridge. When a New York Times reporter telexed the Russian chemists' anti-Pauling resolution to Caltech for a response, Caltech replied with a three-page news release decrying the effects of Lysenkoism and emphasizing Pauling's criticism of Communist science: "If Russian chemists are not allowed to use the resonance theory, or are deprived of scientific freedom in any other direction, Russian scientists will fall behind Western science and Russian technology will also suffer," Pauling was quoted as saying. Subsequent coverage in the Times and Time magazine helped portray Pauling as a defender of Western science against Russian attempts to stifle the truth.

  The Rules of the Game

  While Russians and Americans combed through Pauling's acti
vities for evidence of political incorrectness, Bragg, Astbury, and other English researchers were sifting his protein papers for scientific blunders. By the fall of 1951 they felt that they had found an abundance. While Perutz had confirmed the existence of the alpha helix and its presence in many proteins with his 1.5-angstrom alpha-helix fingerprint, he could not find it in feather-rachis protein, as Pauling had predicted he should; Perutz concluded that Pauling and Corey's proposed feather structure must be wrong. Perutz also thought the proposed model for muscle contraction, which Pauling had hypothesized involved the contraction of pleated sheets into alpha helixes, could not be right because evidence of the alpha pattern was found in both the extended and contracted forms. Bernal was ready to accept the alpha helix for fibrous proteins but was fairly certain that it was not a contributor to the structure of two globular proteins he was working with, ribonuclease and chymotrypsin. The Courtaulds team did not agree with what Pauling had said about the dimensions of their synthetic polypeptides. Pauling's looser gamma helix was being criticized because it had a hole down the center large enough to let in small molecules that could destabilize it. Most disappointingly for Pauling, his proposed structure for collagen—the three-helix cable that he thought did a good job of explaining the substance's resistance to stretching—did not gain support from the English x-ray results.

  Pauling spent much of his time in the latter part of 1951 conceiving answers to these criticisms and revising his structures. He felt the work so important that he turned down the offer of a visiting professorship at Harvard to concentrate on the task; he also put off a planned trip to Europe until he felt more secure about his ideas. The alpha-helix fingerprint in feathers might be hidden because the helixes are out of phase, he noted; muscle might also contain "non-contractile alpha-keratin" which remained in the alpha form all the time. He cleared up a misunderstanding with the Courtaulds group and soon got them to agree that the alpha helix seemed reasonable for their synthetic polypeptides. The gamma helix, however, would have to be abandoned. Pauling had always been uneasy about its stability; by the fall Pauling was backing off from it entirely. As the evidence against his collagen structure mounted, he fell back to a new position, concluding by the end of 1951 that "the structure that we have suggested ... is not quite right. I think that its general aspects are correct, but some small changes will be necessary." Meanwhile, he and Corey came up with two new pleated sheet structures and were also thinking about what they called a "rippled sheet" for some proteins.