Free Radicals - Michael Brooks [39]
When scientists make extraordinary breakthroughs, other scientists are usually quick to step in and try to replicate whatever has been achieved. Stanley’s work was no different: when they read his paper, two British researchers attempted to prepare their own virus crystals according to Stanley’s published recipe. Frederick Bawden and Bill Pirie, however, got rather different results.
Stanley had said that his liquid crystal virus contained 20 per cent nitrogen but no phosphorus or carbohydrates. Bawden and Pirie, on the other hand, found 0.5 per cent phosphorus and 2.5 per cent carbohydrate. This was a significant difference in composition: carry out the right chemical routines on Bawden and Pirie’s mix, and you will get ribonucleic acid – genetic material, in other words. Stanley’s ‘protein-only’ hypothesis was facing a serious challenge. Bawden and Pirie published their findings in Nature in 1936. They questioned whether Stanley really had isolated the tobacco mosaic virus as a crystal. Whatever it was he had isolated, it might not be the infectious agent, they suggested.
In a beautiful piece of quiet anarchy, Stanley then silently backed off from his original claims. He began to assimilate Bawden and Pirie’s findings about phosphorus and carbohydrate into his own research. By 1938, he was declaring that tobacco mosaic virus did indeed contain nucleic acid. But somehow he did not change the angle of his research, or retract his original claims, and in 1946 he was awarded the Nobel Prize in Chemistry. The presentation speech describes his work as ‘one of the most striking discoveries in modern chemistry and biology’ and explicitly states that the prize was for demonstrating that a virus ‘actually is a protein’. Thirty years before Stanley Prusiner’s Nobel Prize split biologists, Wendell Stanley’s Nobel had created a scientific stand-off over the same issue: whether an infectious agent can be just protein. Fortunately, Bawden and Pirie had something with which they could fight the respectability conferred upon Stanley by his Nobel Prize. It’s something that Prusiner also has in spades: charisma.
In science, charisma can work as effectively as evidence. In his autobiography, The Double Helix, James Watson mentions Bawden and Pirie’s gift explicitly. ‘No one could match the smooth erudition of Bawden or the assured nihilism of Pirie,’ he wrote. And so biologists slowly began to desert Stanley and join Bawden and Pirie’s camp. By the early 1950s, the pair were winning out, despite Stanley’s Nobel Prize.
While they nullified one Nobel Prize, Bawden and Pirie were sowing the seeds of another. Watson knew them because he carried out X-ray crystallography work on the structure of the tobacco mosaic virus. Watson’s contract at Cambridge had been terminated, and he was no longer allowed to work on DNA. However, the tobacco mosaic virus was thought to have a helical structure, and that offered a back door into the secrets of DNA. It was, Watson said, ‘the perfect front to mask my continued interest in DNA’.
Bawden and Pirie also inspired Francis Crick. The growing appreciation of the role that nucleic acids played in the tobacco mosaic virus led Crick to his ‘sequence hypothesis’: that the genetic information about an organism is encoded in these nucleic acids. The sequence of molecules in the acid would dictate what kind of protein would be produced.
In 1953, Crick and Watson discovered exactly how it all fitted together – the famous double helix. Three years after that, they published a paper on the structure of small viruses in Nature. They defined a virus as a piece of nucleic acid that carried genetic information. That it wore a protective coat made of inert protein was neither here nor there, they