Structural principles that enable oligomeric small heat-shock protein paralogs to evolve distinct functions

Abstract

Putting distance between protein relatives Many proteins form complexes to function. When the gene for a self-assembling protein duplicates, it might be expected that the related proteins (paralogs) would retain interfaces that would allow coassembly. Hochberg et al. show that the majority of paralogs that oligomerize in fact self-assemble. These paralogs have more diverse functions than those that coassemble, implying that maintaining coassembly would constrain evolution of new function. The authors experimentally investigated how two oligomeric small heat-shock protein paralogs avoid coassembly and found that flexibility at regions outside of the interaction interfaces played a key role. Science , this issue p. 930