title: Arsenite oxidation by the heterotroph Hydrogenophaga sp. str. NT-14: the arsenite oxidase and its physiological electron acceptor.
abstract: Heterotrophic arsenite oxidation by Hydrogenophaga sp. str. NT-14 is coupled to the reduction of oxygen and appears to yield energy for growth. Purification and partial characterization of the arsenite oxidase revealed that it (1). contains two heterologous subunits, AroA (86 kDa) and AroB (16 kDa), (2). has a native molecular mass of 306 kDa suggesting an alpha(3)beta(3) configuration, and (3). contains molybdenum and iron as cofactors. Although the Hydrogenophaga sp. str. NT-14 arsenite oxidase shares similarities to the arsenite oxidases purified from NT-26 and Alcaligenes faecalis, it differs with respect to activity and overall conformation. A c-551-type cytochrome was purified from Hydrogenophaga sp. str. NT-14 and appears to be the physiological electron acceptor for the arsenite oxidase. The cytochrome can also accept electrons from the purified NT-26 arsenite oxidase. A hypothetical electron transport chain for heterotrophic arsenite oxidation is proposed.
authors.affiliation: Department of Microbiology, La Trobe University, 3086, Victoria, Melbourne, Australia.
authors.forename: Rachel N
authors.initials: RN
authors.lastname: vanden Hoven
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Santini
mesh_terms: D000595:Amino Acid Sequence; D042621:Comamonadaceae / Q000201:enzymology*; D045304:Cytochromes c / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D007501:Iron / Q000737:chemistry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D008982:Molybdenum / Q000737:chemistry; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
chemical_list: D021122:Protein Subunits; D008982:Molybdenum; D045304:Cytochromes c; D007501:Iron; D010088:Oxidoreductases; C078179:arsenite oxidase; D010100:Oxygen