title: Nucleotide-dependent oligomerization of ClpB from Escherichia coli.
abstract: Self-association of ClpB (a mixture of 95- and 80-kDa subunits) has been studied with gel filtration chromatography, analytical ultracentrifugation, and electron microscopy. Monomeric ClpB predominates at low protein concentration (0.07 mg/mL), while an oligomeric form is highly populated at >4 mg/mL. The oligomer formation is enhanced in the presence of 2 mM ATP or adenosine 5'-O-thiotriphosphate (ATPgammaS). In contrast, 2 mM ADP inhibits full oligomerization of ClpB. The apparent size of the ATP- or ATPgammaS-induced oligomer, as determined by gel filtration, sedimentation velocity and electron microscopy image averaging, and the molecular weight, as determined by sedimentation equilibrium, are consistent with those of a ClpB hexamer. These results indicate that the oligomerization reactions of ClpB are similar to those of other Hsp100 proteins.
authors.affiliation: Department of Biochemistry, Kansas State University, Manhattan 66506, USA. michalz@ksu.edu
authors.forename: M
authors.initials: M
authors.lastname: Zolkiewski
authors.forename: M
authors.initials: M
authors.lastname: Kessel
authors.forename: A
authors.initials: A
authors.lastname: Ginsburg
authors.forename: M R
authors.initials: MR
authors.lastname: Maurizi
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000737:chemistry*; D000345:Affinity Labels; D002850:Chromatography, Gel; D019281:Dimerization; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D014461:Ultracentrifugation
chemical_list: D000345:Affinity Labels; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D049071:Endopeptidase Clp; C069775:ClpB protein, E coli