title: Role of the N-terminal domain of the chaperone ClpX in the recognition and degradation of lambda phage protein O.
abstract: The ClpXP ATPase-protease complex is a key element of the protein quality control machinery in the cell. ClpX consists of a zinc-binding domain (ZBD) that forms dimers and a AAA(+) domain that arranges into a hexamer in an ATP-dependent manner. Here, we report the binding site of the ClpX substrate λ phage protein O (λO) on ZBD(2) in ClpX using NMR and mutagenesis analysis. λO protein was found to interact with a hydrophobic patch on the larger surface of ZBD(2). The affinity of λO toward ZBD(2) was investigated using a quantitative optical biosensor method of dual polarization interferometry. The data suggest overlapping binding sites of λO and the ClpX cofactor SspB on the ZBD(2). Interestingly, a single key mutation in ZBD was found to enhance the ClpXP-dependent degradation of λO.
authors.affiliation: Department of Biochemistry, University of Toronto, 1 King's College Circle, Medical Sciences Building, Toronto, Ontario M5S 1A8, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Thibault
authors.forename: Walid A
authors.initials: WA
authors.lastname: Houry
mesh_terms: D001665:Binding Sites; D049071:Endopeptidase Clp / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016296:Mutagenesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D054730:Protein Interaction Domains and Motifs; D013499:Surface Properties; D013816:Thermodynamics; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; C027812:O protein, Bacteriophage lambda; D014764:Viral Proteins; C483573:ClpXP protease, E coli; D049071:Endopeptidase Clp