title: A tightly regulated molecular toggle controls AAA+ disaggregase.
abstract: The ring-forming AAA+ protein ClpB cooperates with the DnaK chaperone system to refold aggregated proteins in Escherichia coli. The M domain, a ClpB-specific coiled-coil structure with two wings, motif 1 and motif 2, is essential to disaggregation, but the positioning and mechanistic role of M domains in ClpB hexamers remain unresolved. We show that M domains nestle at the ClpB ring surface, with both M-domain motifs contacting the first ATPase domain (AAA-1). Both wings contribute to maintaining a repressed ClpB activity state. Motif 2 docks intramolecularly to AAA-1 to regulate ClpB unfolding power, and motif 1 contacts a neighboring AAA-1 domain. Mutations that stabilize motif 2 docking repress ClpB, whereas destabilization leads to derepressed ClpB activity with greater unfolding power that is toxic in vivo. Our results underline the vital nature of tight ClpB activity control and elucidate a regulated M-domain toggle control mechanism.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Oguchi
authors.forename: Eva
authors.initials: E
authors.lastname: Kummer
authors.forename: Fabian
authors.initials: F
authors.lastname: Seyffer
authors.forename: Mykhaylo
authors.initials: M
authors.lastname: Berynskyy
authors.forename: Benjamin
authors.initials: B
authors.lastname: Anstett
authors.forename: Regina
authors.initials: R
authors.lastname: Zahn
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Wade
authors.forename: Axel
authors.initials: A
authors.lastname: Mogk
authors.forename: Bernd
authors.initials: B
authors.lastname: Bukau
mesh_terms: D000595:Amino Acid Sequence; D049071:Endopeptidase Clp; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation
chemical_list: D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D049071:Endopeptidase Clp; C069775:ClpB protein, E coli