New insights into the structure and function of the complex between the Escherichia coli Hsp70, DnaK, and its nucleotide-exchange factor, GrpE.

Autor:	Rossi MA; Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA., Pozhidaeva AK; Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA., Clerico EM; Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA., Petridis C; Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA., Gierasch LM; Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA; Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts, USA. Electronic address: gierasch@biochem.umass.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2024 Jan; Vol. 300 (1), pp. 105574. Date of Electronic Publication: 2023 Dec 16.
DOI:	10.1016/j.jbc.2023.105574
Abstrakt:	The 70 kDa heat shock proteins (Hsp70s) play a pivotal role in many cellular functions using allosteric communication between their nucleotide-binding domain (NBD) and substrate-binding domain, mediated by an interdomain linker, to modulate their affinity for protein clients. Critical to modulation of the Hsp70 allosteric cycle, nucleotide-exchange factors (NEFs) act by a conserved mechanism involving binding to the ADP-bound NBD and opening of the nucleotide-binding cleft to accelerate the release of ADP and binding of ATP. The crystal structure of the complex between the NBD of the Escherichia coli Hsp70, DnaK, and its NEF, GrpE, was reported previously, but the GrpE in the complex carried a point mutation (G122D). Both the functional impact of this mutation and its location on the NEF led us to revisit the DnaK NBD/GrpE complex structurally using AlphaFold modeling and validation by solution methods that report on protein conformation and mutagenesis. This work resulted in a new model for the DnaK NBD in complex with GrpE in which subdomain IIB of the NBD rotates more than in the crystal structure, resulting in an open conformation of the nucleotide-binding cleft, which now resembles more closely what is seen in other Hsp/NEF complexes. Moreover, the new model is consistent with the increased ADP off-rate accompanying GrpE binding. Excitingly, our findings point to an interdomain allosteric signal in DnaK triggered by GrpE binding. Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article. (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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