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.

Effects of Metal on the Biochemical Properties of Helicobacter pylori HypB, a Maturation Factor of [NiFe]-Hydrogenase and Urease

“…The participation of metalbinding NTPases in the biosynthetic pathways of complex metallocenters is an emerging trend (30), although whether a common theme of metal-regulated NTP hydrolysis exists is not yet clear. For example, metal-dependent dimerization was observed for CooC (28,29), the ATPase involved in carbon monoxide dehydrogenase biosynthesis, but ATP hydrolysis was not dramatically affected by the addition of nickel. Furthermore, the GTPase dedicated to urease maturation, UreG, binds nickel or zinc with micromolar affinities at a site that likely includes the CxH motif found at a similar location with respect to the GTPase motifs as C106/H107 of HpHypB (5,70,71).…”

Biosynthesis of the Iron-Molybdenum Cofactor of Nitrogenase

“…Such a binding pattern parallels the formation of a possible adenylylated molybdate intermediate during the biosynthesis of molybdopterin cofactors (9). Moreover, another ATPase, CooC, has been implicated in the insertion of nickel into the C-cluster of the carbon monoxide dehydrogenase from Rhodospirillum rubrum (26). Thus, the mobilization of molybdenum by NifH may exemplify a general scheme for metal trafficking in biological systems.…”

AcsF Catalyzes the ATP-dependent Insertion of Nickel into the Ni,Ni-[4Fe4S] Cluster of Acetyl-CoA Synthase

“…The CooC-type cluster harbors 298 sequences and includes all CooC proteins shown to be involved in CODH maturation, such as CooC from R. rubrum (CooC Rr ) (26), CooC3 Ch (27), and CooC from Desulfovibrio vulgaris (CooC Dv ) (28). The CooC-type cluster also encompasses CooC1 from C. hydrogenoformans (CooC1 Ch ), which is a nickel-binding ATPase whose crystal structure has been determined (27,31).…”

“…CooC1 Ch was prepared as previously described (31). For AcsF Ch , 5 to 10 g of frozen cells were resuspended in buffer A (50 mM Tris-HCl, pH 8.0, 100 mM NaCl, 2 mM tris(2-carboxyethyl)phosphine) with a small amount of avidin and lysozyme.…”

“…Common to the MinD-type ATPases is an ATP-dependent dimerization, which is central to their function and a prerequisite to hydrolyze ATP (30). CooC binds Ni(II) through the Cys-X-Cys motifs of two monomers that combine to form a metal binding site within the dimer interface (31,32). Additional proteins support the maturation of the CODH in Rhodospirillum rubrum (25); however, these additional proteins are not conserved in bacteria outside the Rhodospirillaceae and may be functionally replaced by non-homologous isofunctional enzymes in other organisms.…”