It takes a dimer to tango: Oligomeric small heat shock proteins dissociate to capture substrate.

ABSTRACT: Small heat-shock proteins (sHsps) are ubiquitous molecular chaperones, and sHsp mutations or altered expression are linked to multiple human disease states. sHsp monomers assemble into large oligomers with dimeric substructure, and the dynamics of sHsp oligomers has led to major questions about the form that captures substrate, a critical aspect of their mechanism of action. We show here that substructural dimers of two plant dodecameric sHsps, Ta16.9 and homologous Ps18.1, are functional units in the initial encounter with unfolding substrate. We introduced inter-polypeptide disulfide bonds at the two dodecameric interfaces, dimeric and nondimeric, to restrict how their assemblies can dissociate. When disulfide-bonded at the nondimeric interface, mutants of Ta16.9 and Ps18.1 (Ta_CT-AC

SUBMITTER: Santhanagopalan I 

PROVIDER: S-EPMC6314120 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature