title: Fate of arsenate following arsenite oxidation in Agrobacterium tumefaciens GW4.
abstract: The fate of arsenate (As(V) ) generated by microbial arsenite (As(III) ) oxidation is poorly understood. Agrobacterium tumefaciens wild-type strain (GW4) was studied to determine how the cell copes with As(V) generated in batch culture. GW4 grown heterotrophically with mannitol used As(III) as a supplemental energy supply as reflected by enhanced growth and increased cellular levels of NADH and ATP. Under low phosphate (Pi) conditions and presence of As(III) oxidation, up to ∼ 50% of the resulting As(V) was taken up and found associated with the periplasm, membrane or cytoplasm fractions of the cells. Arsenic was found associated with proteins and polar lipids, but not in nucleic acids or sugars. Thin-layer chromatography and gas chromatography-mass spectrometry analysis suggested the presence of arsenolipids in membranes, presumably as part of the bilayer structure of the cell membrane and replacing Pi under Pi-limiting conditions. The potential role of a Pi-binding protein (PstS) for As(V) uptake was assessed with the His-tag purified protein. Intrinsic tryptophan fluorescence spectra analysis suggests that PstS can bind As(V) , but with lower affinity as compared with Pi. In early stationary phase cells, the As(V)  : Pi ratio was approximately 4.3 and accompanied by an altered cell ultrastructure.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Shengzhe
authors.initials: S
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Jingxin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Christopher
authors.initials: C
authors.lastname: Rensing
authors.affiliation: Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, 59717, USA.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: McDermott
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Gejiao
authors.initials: G
authors.lastname: Wang
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D016960:Agrobacterium tumefaciens / Q000378:metabolism*; D001149:Arsenates / Q000378:metabolism*; D001151:Arsenic / Q000378:metabolism; D018053:Arsenites / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry*; D008353:Mannitol / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction
chemical_list: D001149:Arsenates; D018053:Arsenites; D009243:NAD; D008353:Mannitol; D000255:Adenosine Triphosphate; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid