Family

Chaperone DnaK (IPR012725)

Short name: Chaperone_DnaK

Family relationships

Description

Molecular chaperones are a diverse family of proteins that function to protect proteins in the intracellular milieu from irreversible aggregation during synthesis and in times of cellular stress. The bacterial molecular chaperone DnaK is an enzyme that couples cycles of ATP binding, hydrolysis, and ADP release by an N-terminal ATP-hydrolysing domain to cycles of sequestration and release of unfolded proteins by a C-terminal substrate binding domain. In prokaryotes, the grpE protein is a co-chaperone for DnaK, and acts as a nucleotide exchange factor, stimulating the rate of ADP release 5000-fold [PMID: 8280473]. DnaK is itself a weak ATPase; ATP hydrolysis by DnaK is stimulated by its interaction with another co-chaperone, DnaJ. Thus the co-chaperones DnaJ and GrpE are capable of tightly regulating the nucleotide-bound and substrate-bound state of DnaK in ways that are necessary for the normal housekeeping functions and stress-related functions of the DnaK molecular chaperone cycle.

Members of this family are the chaperone DnaK, of the DnaK-DnaJ-GrpE chaperone system. All members of the seed alignment were taken from completely sequenced bacterial or archaeal genomes and (except for the Mycoplasma sequence) found clustered with other genes of this systems. This entry excludes DnaK homologues that are not DnaK itself, such as the heat shock cognate protein HscA (IPR010236). However, it is not designed to distinguish among DnaK paralogs in eukaryotes. Note that a number of DnaK genes have shadow ORFs in the same reverse (relative to dnaK) reading frame, a few of which have been assigned glutamate dehydrogenase activity. The significance of this observation is unclear; the lengths of such shadow ORFs are highly variable as if the presumptive protein product is not conserved.

GO terms

Biological Process

GO:0006457 protein folding

Molecular Function

GO:0005524 ATP binding
GO:0051082 unfolded protein binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
TIGRFAMs
HAMAP