9DYU

Assembly and functional mechanisms of the Hsp70-Hsp40 chaperone machinery

Summary for 9DYU

• Entry DOI: 10.2210/pdb9dyu/pdb
• NMR Information: BMRB: 52640
• Descriptor: Chaperone protein DnaK (1 entity in total)
• Functional Keywords: dnaj2 and dnak fusion, structural protein
• Biological source: Thermus thermophilus
• Total number of polymer chains: 1
• Total formula weight: 14004.81

Authors

Jiang, Y.,Ibrahim, Z.,Xia, Y.,Kalodimos, C.G. (deposition date: 2024-10-14, release date: 2025-10-22, Last modification date: 2025-11-19)

Primary citation

Jiang, Y.,Ibrahim, Z.,Xia, Y.,Clay, M.,Myasnikov, A.,Immadisetty, K.,Xia, Z.,Tang, L.,Rossi, P.,Ganguly, P.,Liu, J.,Miller, D.,Che, M.,Palacios, S.M.,Kramer, G.,Bukau, B.,Kalodimos, C.G.
Mechanisms of assembly and function of the Hsp70-Hsp40 chaperone machinery.
Mol.Cell, 85:4032-, 2025

PubMed Abstract: Hsp70 and Hsp40 molecular chaperones form a central machinery that remodels client proteins involved in numerous biological processes. Here, we integrated cryo-electron microscopy and nuclear magnetic resonance spectroscopy to determine the architecture of the full-length Hsp70-Hsp40 machinery. The structure of the complex in a physiologically inhibited state reveals distinct regulatory mechanisms. In the active state, the Hsp40 glycine-phenylalanine (G/F)-rich region acts as a pseudo-substrate for Hsp70, directly modulating refolding. This region also maintains Hsp40 in an autoinhibited state; upon binding to Hsp70, the inhibition is disrupted, exposing a cryptic client-binding site that enables client engagement and refolding. Transitions between these states are central to controlling refolding efficiency. Disrupting either the autoinhibited state or the G/F-Hsp70 interaction impairs function and elicits a compensatory heat shock response in cells. Our findings uncover the regulatory dynamics of a fundamental chaperone system, with broad implications for understanding protein homeostasis and the cellular response to stress.

PubMed: 41092901
DOI: 10.1016/j.molcel.2025.09.023

Experimental method

SOLUTION NMR