title: Allosteric opening of the polypeptide-binding site when an Hsp70 binds ATP.
abstract: The 70-kilodalton (kDa) heat-shock proteins (Hsp70s) are ubiquitous molecular chaperones essential for cellular protein folding and proteostasis. Each Hsp70 has two functional domains: a nucleotide-binding domain (NBD), which binds and hydrolyzes ATP, and a substrate-binding domain (SBD), which binds extended polypeptides. NBD and SBD interact little when in the presence of ADP; however, ATP binding allosterically couples the polypeptide- and ATP-binding sites. ATP binding promotes polypeptide release; polypeptide rebinding stimulates ATP hydrolysis. This allosteric coupling is poorly understood. Here we present the crystal structure of an intact ATP-bound Hsp70 from Escherichia coli at 1.96-Å resolution. The ATP-bound NBD adopts a unique conformation, forming extensive interfaces with an SBD that has changed radically, having its α-helical lid displaced and the polypeptide-binding channel of its β-subdomain restructured. These conformational changes, together with our biochemical assays, provide a structural explanation for allosteric coupling in Hsp70 activity.
authors.affiliation: Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, USA.
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Qi
authors.forename: Evans Boateng
authors.initials: EB
authors.lastname: Sarbeng
authors.forename: Qun
authors.initials: Q
authors.lastname: Liu
authors.forename: Katherine Quynh
authors.initials: KQ
authors.lastname: Le
authors.forename: Xinping
authors.initials: X
authors.lastname: Xu
authors.forename: Hongya
authors.initials: H
authors.lastname: Xu
authors.forename: Jiao
authors.initials: J
authors.lastname: Yang
authors.forename: Jennifer Li
authors.initials: JL
authors.lastname: Wong
authors.forename: Christina
authors.initials: C
authors.lastname: Vorvis
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Hendrickson
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Qinglian
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli; C095973:SSA1 protein, S cerevisiae