4b9q
Open conformation of ATP-bound Hsp70 homolog DnaK
Structural highlights
FunctionDNAK_ECOLI Plays an essential role in the initiation of phage lambda DNA replication, where it acts in an ATP-dependent fashion with the DnaJ protein to release lambda O and P proteins from the preprimosomal complex. DnaK is also involved in chromosomal DNA replication, possibly through an analogous interaction with the DnaA protein. Also participates actively in the response to hyperosmotic shock.[HAMAP-Rule:MF_00332] Publication Abstract from PubMedCentral to the chaperone function of Hsp70s is the transition between open and closed conformations of their polypeptide substrate binding domain (SBD), which is regulated through an allosteric mechanism via ATP binding and hydrolysis in their nucleotide binding domain (NBD). Although the structure of the closed conformation of Hsp70s is well studied, the open conformation has remained elusive. Here, we report on the 2.4 A crystal structure of the ATP-bound open conformation of the Escherichia coli Hsp70 homolog DnaK. In the open DnaK structure, the beta sheet and alpha-helical lid subdomains of the SBD are detached from one another and docked to different faces of the NBD. The contacts between the beta sheet subdomain and the NBD reveal the mechanism of allosteric regulation. In addition, we demonstrate that docking of the beta sheet and alpha-helical lid subdomains to the NBD is a sequential process influenced by peptide and protein substrates. Structure and Dynamics of the ATP-Bound Open Conformation of Hsp70 Chaperones.,Kityk R, Kopp J, Sinning I, Mayer MP Mol Cell. 2012 Nov 1. pii: S1097-2765(12)00823-4. doi:, 10.1016/j.molcel.2012.09.023. PMID:23123194[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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