title: The 1.6-A crystal structure of the class of chaperones represented by Escherichia coli Hsp31 reveals a putative catalytic triad.
abstract: Heat shock proteins (Hsps) play essential protective roles under stress conditions by preventing the formation of protein aggregates and degrading misfolded proteins. EcHsp31, the yedU (hchA) gene product, is a representative member of a family of chaperones that alleviates protein misfolding by interacting with early unfolding intermediates. The 1.6-A crystal structure of the EcHsp31 dimer reveals a system of hydrophobic patches, canyons, and grooves, which may stabilize partially unfolded substrate. The presence of a well conserved, yet buried, triad in each two-domain subunit suggests a still unproven hydrolytic function of the protein. A flexible extended linker between the A and P domains may play a role in conformational flexibility and substrate binding. The alpha-beta sandwich of the EcHsp31 monomer shows structural similarity to PhPI, a protease belonging to the DJ-1 superfamily. The structure-guided sequence alignment indicates that Hsp31 homologs can be divided in three classes based on variations in the P domain that dramatically affect both oligomerization and catalytic triad formation.
authors.affiliation: Biomolecular Structure Center, P.O. Box 357742, University of Washington, Seattle, WA 98195, USA. paulene@u.washington.edu
authors.forename: Paulene M
authors.initials: PM
authors.lastname: Quigley
authors.forename: Konstantin
authors.initials: K
authors.lastname: Korotkov
authors.forename: Francois
authors.initials: F
authors.lastname: Baneyx
authors.forename: Wim G J
authors.initials: WG
authors.lastname: Hol
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D019711:Pyrococcus / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity
chemical_list: D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D021122:Protein Subunits; C469996:hchA protein, E coli; D010450:Endopeptidases