title: Structure and dynamics of the ATP-bound open conformation of Hsp70 chaperones.
abstract: Central to the chaperone function of Hsp70s is the transition between open and closed conformations of their polypeptide substrate binding domain (SBD), which is regulated through an allosteric mechanism via ATP binding and hydrolysis in their nucleotide binding domain (NBD). Although the structure of the closed conformation of Hsp70s is well studied, the open conformation has remained elusive. Here, we report on the 2.4 Å crystal structure of the ATP-bound open conformation of the Escherichia coli Hsp70 homolog DnaK. In the open DnaK structure, the β sheet and α-helical lid subdomains of the SBD are detached from one another and docked to different faces of the NBD. The contacts between the β sheet subdomain and the NBD reveal the mechanism of allosteric regulation. In addition, we demonstrate that docking of the β sheet and α-helical lid subdomains to the NBD is a sequential process influenced by peptide and protein substrates.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Kityk
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kopp
authors.forename: Irmgard
authors.initials: I
authors.lastname: Sinning
authors.forename: Matthias P
authors.initials: MP
authors.lastname: Mayer
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D019943:Amino Acid Substitution; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D006860:Hydrogen Bonding; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D040681:Structural Homology, Protein
chemical_list: D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D000255:Adenosine Triphosphate; C063842:dnaK protein, E coli