>TIGR02349 DnaJ_bact chaperone protein DnaJ; InterPro: IPR012724 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-hydrolizing domain to cycles of sequestration and release of unfolded proteins by a C-terminal substrate binding domain. Dimeric GrpE is the co-chaperone for DnaK, and acts as a nucleotide exchange factor, stimulating the rate of ADP release 5000-fold . 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. Besides stimulating the ATPase activity of DnaK through its J-domain, DnaJ also associates with unfolded polypeptide chains and prevents their aggregation . Thus, DnaK and DnaJ may bind to one and the same polypeptide chain to form a ternary complex. The formation of a ternary complex may result in cis-interaction of the J-domain of DnaJ with the ATPase domain of DnaK. An unfolded polypeptide may enter the chaperone cycle by associating first either with ATP-liganded DnaK or with DnaJ. DnaK interacts with both the backbone and side chains of a peptide substrate; it thus shows binding polarity and admits only L-peptide segments. In contrast, DnaJ has been shown to bind both L- and D-peptides and is assumed to interact only with the side chains of the substrate. DnaJ comprises a 70-residue N-terminal domain (the J-domain); a 30-residue glycine-rich region (the G-domain); a central domain containing 4 repeats of a CxxCxGxG motif (the CRR-domain); and a 120-170 residue C-terminal region. The J- and CRR-domains are found in many prokaryotic and eukaryotic proteins , either together or separately. This entry mostly consists of bacterial forms of DnaJ. The three components of the DnaK-DnaJ-GrpE system are typically encoded by consecutive genes. DnaJ homologues occur in many genomes, typically not encoded near DnaK and GrpE-like genes. Most such proteins are not included in this family, though some chloroplast homologues are included; GO: 0005524 ATP binding, 0051082 unfolded protein binding, 0006457 protein folding, 0009408 response to heat.

Probab=96.50  E-value=0.00094  Score=45.57  Aligned_cols=42  Identities=21%  Similarity=0.372  Sum_probs=29.8

Q ss_pred             HHHHHHHHHHCCCCCCCHHHHHHHHHHHHHHHCCCCCCCCHHHHHHHHHHHHHHHHHHH
Q ss_conf             88976998617773288999999999999996578899798799999999999999996
Q gi|254780585|r  129 SMQFNAFEILGLLSDSSPEEIRGRYKDLVKKHHPDANGGDRGSEERFQAVIQAYKILKK  187 (191)
Q Consensus       129 ~~~~~Al~~Lgl~~~~~~~~ik~~yk~lvk~~HPD~n~g~~~~ee~~~~I~~Ay~~Lk~  187 (191)
T Consensus        15 ~EIKKAYRkLA~kYHPD~--------------Nkg---n~~~AEeKFKEi~EAYeVLSD   56 (386)
T TIGR02349        15 EEIKKAYRKLAKKYHPDR--------------NKG---NDKEAEEKFKEINEAYEVLSD   56 (386)
T ss_pred             HHHHHHHHHHHHHCCCCC--------------CCC---CCCCHHHHHHHHHHHHHCCCC
T ss_conf             999999998888517888--------------888---883756765788877530689