title: Mutations in the DnaK chaperone affecting interaction with the DnaJ cochaperone.
abstract: 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 the Escherichia 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.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Universität Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany.
authors.forename: C S
authors.initials: CS
authors.lastname: Gässler
authors.forename: A
authors.initials: A
authors.lastname: Buchberger
authors.forename: T
authors.initials: T
authors.lastname: Laufen
authors.forename: M P
authors.initials: MP
authors.lastname: Mayer
authors.forename: H
authors.initials: H
authors.lastname: Schröder
authors.forename: A
authors.initials: A
authors.lastname: Valencia
authors.forename: B
authors.initials: B
authors.lastname: Bukau
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008156:Luciferases / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D008156:Luciferases; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli