title: Poly-L-lysine enhances the protein disaggregation activity of ClpB.
abstract: The Hsp100 protein ClpB is a member of the AAA+ protein family that mediates the solubilization of aggregated proteins in cooperation with the DnaK chaperone system. Unstructured polypeptides such as casein or poly-L-lysine have been shown to stimulate the ATPase activity of ClpB and thus may both act as substrates. Here we compared the effects of alpha-casein and poly-L-lysine on the ATPase and chaperone activities of ClpB. alpha-Casein stimulated ATP hydrolysis by both AAA domains of ClpB and inhibited the ClpB-dependent solubilization of aggregated proteins if present in excess. In contrast, poly-L-lysine stimulated exclusively the ATPase activity of the second AAA domain and increased the disaggregation activity of ClpB. Thus poly-L-lysine does not act as substrate, but rather represents an effector molecule, which enhances the chaperone activity of ClpB.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Universität Freiburg, Freiburg, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Strub
authors.forename: Christian
authors.initials: C
authors.lastname: Schlieker
authors.forename: Bernd
authors.initials: B
authors.lastname: Bukau
authors.forename: Axel
authors.initials: A
authors.lastname: Mogk
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002364:Caseins / Q000378:metabolism; D049071:Endopeptidase Clp; D029968:Escherichia coli Proteins / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006868:Hydrolysis; D008156:Luciferases / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D011107:Polylysine / Q000378:metabolism*; D017510:Protein Folding
chemical_list: D002364:Caseins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011107:Polylysine; D000255:Adenosine Triphosphate; D008156:Luciferases; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C069775:ClpB protein, E coli