title: CooC1 from Carboxydothermus hydrogenoformans is a nickel-binding ATPase.
abstract: The maturation of nickel-dependent enzymes requires the participation of several accessory proteins. Typically the hydrolysis of nucleotides is necessary for the final metal transfer steps. The ATPase CooC has been implicated in the insertion of nickel into the Ni,Fe cluster (C cluster) of the carbon monoxide dehydrogenase from Rhodospirillum rubrum. Analysis of the amino acid sequence of CooC suggests the presence of motifs typical for the MinD family of SIMIBI class NTPases, which contain a deviant Walker A motif. The genome of the carboxidotrophic hydrogenogenic bacterium Carboxydothermus hydrogenoformans contains three open reading frames with distinct sequence homology to CooC from R. rubrum. We overproduced, isolated, and studied CooC1 from C. hydrogenoformans. As-isolated CooC1 is monomeric in the absence of ligands but dimerizes in the presence of either nickel, ADP, or ATP. CooC1 shows ATPase activity, and the ADP- and ATP-bound dimeric states are distinguished by their stability. The K8A mutant of CooC1, in which alanine replaces the signature lysine typical for the deviant Walker A motif in the MinD family, is incapable of both ATP hydrolysis and ATP-dependent dimerization. This corroborates that CooC1 is indeed a member of the MinD family and suggests an analogous dynamic equilibrium between monomeric and dimeric states. CooC proteins are involved in the insertion of nickel into carbon monoxide dehydrogenases, and we found that one CooC1 dimer binds one Ni(II) ion with nanomolar affinity. Ni-induced dimerization and the Ni(II)-CooC1 stoichiometry suggest that the Ni-binding site of CooC1 occurs in the dimer interface.
authors.affiliation: Bioinorganic Chemistry, University of Bayreuth, 95447 Bayreuth, Germany.
authors.forename: Jae-Hun
authors.initials: JH
authors.lastname: Jeoung
authors.forename: Till
authors.initials: T
authors.lastname: Giese
authors.forename: Marlene
authors.initials: M
authors.lastname: Grünwald
authors.forename: Holger
authors.initials: H
authors.lastname: Dobbek
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism*; D000445:Aldehyde Oxidoreductases / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002942:Circular Dichroism; D003124:Colorimetry; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D008239:Lysine / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D009532:Nickel / Q000737:chemistry / Q000378:metabolism*; D012247:Rhodospirillum rubrum / Q000201:enzymology; D013056:Spectrophotometry, Ultraviolet; D046968:Thermoanaerobacter / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D009532:Nickel; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase; D000251:Adenosine Triphosphatases; D008239:Lysine