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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / chemistry
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Adenosine Triphosphatases / genetics
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Adenosine Triphosphate / metabolism*
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Allosteric Regulation
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Amino Acid Sequence
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Binding Sites
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Conserved Sequence
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Crystallography, X-Ray
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Dimerization
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Escherichia coli Proteins / chemistry*
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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HSP70 Heat-Shock Proteins / chemistry*
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HSP70 Heat-Shock Proteins / genetics
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HSP70 Heat-Shock Proteins / metabolism
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Hydrogen Bonding
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Models, Molecular
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Molecular Sequence Data
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Mutation, Missense
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Peptides / metabolism
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Protein Binding
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Protein Conformation
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Protein Folding
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Protein Interaction Mapping
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Protein Structure, Tertiary
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae Proteins / chemistry
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Saccharomyces cerevisiae Proteins / genetics
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Sequence Alignment
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Sequence Homology, Amino Acid
Substances
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Escherichia coli Proteins
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HSP70 Heat-Shock Proteins
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Peptides
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Adenosine Triphosphate
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Adenosine Triphosphatases
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dnaK protein, E coli
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SSA1 protein, S cerevisiae
Associated data
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PDB/4JN4
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PDB/4JNE
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PDB/4JNF