Open AccessMutations in the DnaK chaperone affecting interaction with the DnaJ cochaperone
Author(s) -
Claudia S. Gässler,
Alexander Buchberger,
Thomas Laufen,
Mathias Mayer,
Hartwig Schröder,
Alfonso Valencia,
Bernd Bukau
Publication year - 1998
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.95.26.15229
Subject(s) - atp hydrolysis , chaperone (clinical) , atpase , biology , biochemistry , escherichia coli , adenosine triphosphate , escherichia coli proteins , plasma protein binding , microbiology and biotechnology , biophysics , binding site , cyclic nucleotide binding domain , enzyme , peptide sequence , gene , medicine , pathology
Hsp70 chaperones assist protein folding by ATP-controlled cycles of substrate binding and release. ATP hydrolysis is the rate-limiting step of the ATPase cycle that causes locking in of substrates into the substrate-binding cavity of Hsp70. This key step is strongly stimulated by DnaJ cochaperones. We show for theEscherichia coli Hsp70 homolog, DnaK, that stimulation by DnaJ requires the linked ATPase and substrate-binding domains of DnaK. Functional interaction with DnaJ is affected by mutations in an exposed channel located in the ATPase domain of DnaK. It is proposed that binding to this channel, possibly involving the J-domain, allows DnaJ to couple substrate binding with ATP hydrolysis by DnaK. Evolutionary conservation of the channel and the J-domain suggests conservation of the mechanism of action of DnaJ proteins.