Surprising amyloid structure solved
Celia Henry Arnaud · C&EN Global Enterprise · 2017
When Meytal Landau, a structural biologist at Technion—Israel Institute of Technology, recently solved the structure of some peptide fibrils she believed were amyloids, she nearly fell out of her chair. She expected to see the β-sheet architecture that’s common to all known amyloid fibrils. Instead, she saw the first known α-helical version (Science 2017, DOI: 10.1126/science.aaf4901). Amyloid fibrils are protein aggregates that pack together to form long strands. Many of these fibrils are involved in diseases, such as the amyloid-β plaques in Alzheimer’s and the α-synuclein aggregates in Parkinson’s. The β-sheet structural motif had been so ubiquitous among amyloids that researchers thought it was required in order for the aggregates to form. But that may not be the case. PSMα3 is the most cytotoxic member of a family of peptides secreted by the bacterium Staphylococcus aureus. It’s an example of a “functional amyloid,” one that is beneficial rather than harmful