4ani
From Proteopedia
Structural basis for the intermolecular communication between DnaK and GrpE in the DnaK chaperone system from Geobacillus kaustophilus HTA426
Structural highlights
FunctionGRPE_GEOKA Participates actively in the response to hyperosmotic and heat shock by preventing the aggregation of stress-denatured proteins, in association with DnaK and GrpE. It is the nucleotide exchange factor for DnaK and may function as a thermosensor. Unfolded proteins bind initially to DnaJ; upon interaction with the DnaJ-bound protein, DnaK hydrolyzes its bound ATP, resulting in the formation of a stable complex. GrpE releases ADP from DnaK; ATP binding to DnaK triggers the release of the substrate protein, thus completing the reaction cycle. Several rounds of ATP-dependent interactions between DnaJ, DnaK and GrpE are required for fully efficient folding (By similarity). Publication Abstract from PubMedThe conserved, ATP-dependent bacterial DnaK chaperones process client substrates with the aid of the co-chaperones DnaJ and GrpE. However, in the absence of structural information, how these proteins communicate with each other cannot be fully delineated. For the study reported here, we solved the crystal structure of a full-length Geobacillus kaustophilus HTA426 GrpE homodimer in complex with a nearly full-length G. kaustophilus HTA426 DnaK that contains the interdomain linker (acting as a pseudo-substrate), and the N-terminal nucleotide-binding and C-terminal substrate-binding domains at 4.1-A resolution. Each complex contains two DnaKs and two GrpEs, which is a stoichiometry that has not been found before. The long N-terminal GrpE alpha-helices stabilize the linker of DnaK in the complex. Furthermore, interactions between the DnaK substrate-binding domain and the N-terminal disordered region of GrpE may accelerate substrate release from DnaK. These findings provide molecular mechanisms for substrate binding, processing, and release during the Hsp70 chaperone cycle. Crystal Structure of DnaK Protein Complexed with Nucleotide Exchange Factor GrpE in DnaK Chaperone System: INSIGHT INTO INTERMOLECULAR COMMUNICATION.,Wu CC, Naveen V, Chien CH, Chang YW, Hsiao CD J Biol Chem. 2012 Jun 15;287(25):21461-70. Epub 2012 Apr 27. PMID:22544739[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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