Conformational equilibria in allosteric control of Hsp70 chaperones.

Publication Type:

Journal Article

Source:

Mol Cell (2021)

Abstract:

<p>Heat-shock proteins of 70&nbsp;kDa (Hsp70s) are vital for all life and are notably important in protein folding. Hsp70s use ATP binding and hydrolysis at a nucleotide-binding domain (NBD) to control the binding and release of client polypeptides at a substrate-binding domain (SBD); however, the mechanistic basis for this allostery has been elusive. Here, we first characterize biochemical properties of selected domain-interface mutants in bacterial Hsp70 DnaK. We then develop a theoretical model for allosteric equilibria among Hsp70 conformational states to explain the observations: a restraining state, Hsp70-ATP, restricts ATP hydrolysis and binds peptides poorly, whereas a stimulating state, Hsp70-ATP, hydrolyzes ATP rapidly and has high intrinsic substrate affinity but rapid binding kinetics. We support this model for allosteric regulation with DnaK structures obtained in the postulated stimulating state S with biochemical tests of the S-state interface and with improved peptide-binding-site definition in an R-state structure.</p>

PDB: 
7KRV, 7KRW, 7KRT, 7KO2, 7KRU
Detector: 
PILATUS
EIGER
Beamline: 
24-ID-C
24-ID-E