Prions have been a tough sell. Against a backdrop of the "DNA to RNA to protein" credo, the idea that the same amino acid sequence could exist in multiple forms, both normal and deranged, seemed like heresy. But since Stanley Prusiner, a professor of neurology, virology, and biochemistry at the University of California, San Francisco (UCSF), named the agent that causes the transmissible spongiform encephalopathies (TSEs) "proteinaceous infectious particles" in 1982,1 evidence has been steadily accumulating that these prion proteins can indeed set up a deadly chain reaction that renders the brains of 85 mammalian species similar in appearance to Swiss cheese.
Yet despite the mounting evidence, many demonstrations of prion action have been inferred, indirect, or incomplete. A view of how the same molecule can take on different guises has been lacking--until now. Thomas James, chairman of the department of pharmaceutical chemistry at UCSF, with Prusiner and others, has ...
