En route to an amyloid fibril

Among the villains in human diseases are amyloid fibrils, long and tough structures that self-assemble from misfolded proteins (see Physics Today, June 2013, page 16). Unraveling the actual assembly process is becoming increasingly important as research shows that some so-called intermediates—small structures that arise and then vanish during the assembly—have a large impact on the ensuing disease. But the transience of those intermediates makes them difficult to study. A team led by Martin Zanni of the University of Wisconsin has now used rapid-scan two-dimensional IR spectroscopy to watch amylin peptides as they aggregate into fibrils that are implicated in type-2 diabetes. (For more on multidimensional spectroscopy, see the article by Steven Cundiff and Shaul Mukamel, Physics Today, July 2013, page 44.) One element of all fibrils is the β sheet, an adjacent stacking of short strings of peptides known as β strands. The researchers found that...