Researchers have probed the structure of the yeast prion protein Sup35, and discovered how structural changes between different prion strains can influence their infectivity and change the phenotypes they cause.
Prions, infectious proteins that cause a variety of diseases in different animals, occur as different strains. Online in Nature, Jonathan S. Weissman and colleagues present a comprehensive structural analysis of the complete, unmodified yeast Sup35 prion protein in two distinct infectious conformations. Both have an overlapping core of amyloid protein, comprising a glutamine/asparagine-rich first 40 residues. But in the weakest strain the structure is extended to 70 amino acids, explaining its higher stability and weaker propagating potential.
The team have succeeded where others have struggled. Previous structural studies had to make compromises, such as the use of small peptides or bulky modifying groups, to overcome technical challenges associated with the structural analyses of protein aggregates.
Jonathan S. Weissman (University of California, San Francisco, CA, USA)
(C) Nature press release.
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