title: Allosteric signal transmission in the nucleotide-binding domain of 70-kDa heat shock protein (Hsp70) molecular chaperones.
abstract: The 70-kDa heat shock protein (Hsp70) chaperones perform a wide array of cellular functions that all derive from the ability of their N-terminal nucleotide-binding domains (NBDs) to allosterically regulate the substrate affinity of their C-terminal substrate-binding domains in a nucleotide-dependent mechanism. To explore the structural origins of Hsp70 allostery, we performed NMR analysis on the NBD of DnaK, the Escherichia coli Hsp70, in six different states (ligand-bound or apo) and in two constructs, one that retains the conserved and functionally crucial portion of the interdomain linker (residues ) and another that lacks the linker. Chemical-shift perturbation patterns identify residues at subdomain interfaces that constitute allosteric networks and enable the NBD to act as a nucleotide-modulated switch. Nucleotide binding results in changes in subdomain orientations and long-range perturbations along subdomain interfaces. In particular, our findings provide structural details for a key mechanism of Hsp70 allostery, by which information is conveyed from the nucleotide-binding site to the interdomain linker. In the presence of ATP, the linker binds to the edge of the IIA β-sheet, which structurally connects the linker and the nucleotide-binding site. Thus, a pathway of allosteric communication leads from the NBD nucleotide-binding site to the substrate-binding domain via the interdomain linker.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Zhuravleva
authors.forename: Lila M
authors.initials: LM
authors.lastname: Gierasch
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000494:Allosteric Regulation / Q000502:physiology; D001665:Binding Sites; D004926:Escherichia coli / Q000737:chemistry* / 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; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D015398:Signal Transduction / Q000502:physiology; D013329:Structure-Activity Relationship
chemical_list: D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D000255:Adenosine Triphosphate; C063842:dnaK protein, E coli