title: Structural insights into the chaperone activity of the 40-kDa heat shock protein DnaJ: binding and remodeling of a native substrate.
abstract: Hsp40 chaperones bind and transfer substrate proteins to Hsp70s and regulate their ATPase activity. The interaction of Hsp40s with native proteins modifies their structure and function. A good model for this function is DnaJ, the bacterial Hsp40 that interacts with RepE, the repressor/activator of plasmid F replication, and together with DnaK regulates its function. We characterize here the structure of the DnaJ-RepE complex by electron microscopy, the first described structure of a complex between an Hsp40 and a client protein. The comparison of the complexes of DnaJ with two RepE mutants reveals an intrinsic plasticity of the DnaJ dimer that allows the chaperone to adapt to different substrates. We also show that DnaJ induces conformational changes in dimeric RepE, which increase the intermonomeric distance and remodel both RepE domains enhancing its affinity for DNA.
authors.affiliation: Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología, CNB-CSIC, Darwin 3, 28049 Madrid, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Cuéllar
authors.forename: Judit
authors.initials: J
authors.lastname: Perales-Calvo
authors.forename: Arturo
authors.initials: A
authors.lastname: Muga
authors.forename: José María
authors.initials: JM
authors.lastname: Valpuesta
authors.forename: Fernando
authors.initials: F
authors.lastname: Moro
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005144:F Factor / Q000235:genetics / Q000378:metabolism*; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D046912:Multiprotein Complexes; C074164:RepE protein, E coli; D012097:Repressor Proteins; C063842:dnaK protein, E coli
keywords: Chaperones; DnaJ; Electron Microscopy (EM); Heat Shock Protein; Hsp40; Protein Complexes; Protein Conformation; Protein Folding; Protein Structure