title: A conserved loop in the ATPase domain of the DnaK chaperone is essential for stable binding of GrpE.
abstract: The activity of DnaK (Hsp70) chaperones in assisting protein folding relies on DnaK binding and ATP-controlled release of protein substrates. The ATPase activity of DnaK is tightly controlled by the nucleotide exchange factor GrpE. We find that GrpE interacts stably with the amino-terminal ATPase domain of DnaK. Analysis of the mutant DnaK756 protein, which has a lower affinity for GrpE, reveals a role for residue Gly 32 in GrpE binding. Gly 32 is located in an exposed loop near the nucleotide binding site of DnaK. Deletion of this loop prevents stable GrpE binding, ATPase stimulation by GrpE, and DnaK chaperone activity. Conservation of this loop within the Hsp70 family suggests that cooperation between Hsp70 and GrpE-like proteins may be a general feature of this class of chaperone.
authors.affiliation: Zentrum für Molekulare Biologie, Universität Heidelberg, FRG.
authors.forename: A
authors.initials: A
authors.lastname: Buchberger
authors.forename: H
authors.initials: H
authors.lastname: Schröder
authors.forename: M
authors.initials: M
authors.lastname: Büttner
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* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D017124:Conserved Sequence; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D017354:Point Mutation; D011487:Protein Conformation; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C068113:GrpE protein, Bacteria; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli