title: Nucleotide utilization requirements that render ClpB active as a chaperone.
abstract: ClpB is a member of the AAA+ superfamily that forms a ring-shaped homohexamer. Each protomer contains two nucleotide binding domains arranged in two rings that hydrolyze ATP. We extend here previous studies on ClpB nucleotide utilization requirements by using an experimental approach that maximizes random incorporation of different subunits into the protein hexamer. Incorporation of one subunit unable to bind or hydrolyze ATP knocks down the chaperone activity, while the wt hexamer can accommodate two mutant subunits that hydrolyze ATP in only one protein ring. Four subunits seem to build the functional cooperative unit, provided that one of the protein rings contains active nucleotide binding sites.
authors.affiliation: Unidad de Biofísica (CSIC-UPV/EHU), and Departamento de Bioquímica y BiologíaMolecular (UPV/EHU), Facultad de Ciencia y Tecnología, Universidad del País Vasco, P.O. Box 644, Bilbao, Spain.
authors.forename: Urko
authors.initials: U
authors.lastname: del Castillo
authors.forename: José Angel
authors.initials: JA
authors.lastname: Fernández-Higuero
authors.forename: Sergio
authors.initials: S
authors.lastname: Pérez-Acebrón
authors.forename: Fernando
authors.initials: F
authors.lastname: Moro
authors.forename: Arturo
authors.initials: A
authors.lastname: Muga
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002850:Chromatography, Gel; D049071:Endopeptidase Clp; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009711:Nucleotides; D000255:Adenosine Triphosphate; D049071:Endopeptidase Clp; C069775:ClpB protein, E coli