title: [Arsenic metabolism in purple nonsulfur bacteria].
abstract: OBJECTIVE
  To elucidate the arsenic metabolic pathway of purple nonsulfur bacteria (PNSB).
  
  
  METHODS
  We investigated the distribution within their genomes, organization, composition, arrangement, core genes and coding proteins of arsenic gene clusters found in complete genome from 17 strains of PNSB by comparing the genomes analysis, and studied the arsenic metabolism in 3 members of PNSB under anaerobic conditions by UV-Vis and HPLC-ICP-MS.
  
  
  RESULTS
  Arsenate reduction and arsenite methylation pathways mediated by ars operon are the dominating arsenic metabolic processes. The arsenic gene clusters differ vastly in composition and arrangement. Some members of PNSB evolved two independently families of arsenate reduction genes (arsC). The cells of Rhodopseudomonas palustris CQV97, Rhodobacter azotoformans 134K20 and Rhodobacter capsulatus XJ-1 could reduce As (V) to As (III), whereas As (III) could not be transformed back to As (V). Higher concentration phosphate competitively inhibited arsenate toxicity to cells.
  
  
  CONCLUSIONS
  Our investigations shed light on the evolution and functional implications in arsenic gene clusters of PNSB, and support the notion that arsenate reduction and arsenite methylation appears to be the dominant process in PNSB.
authors: Department of Bioengineering and Biotechnology, Huaqiao University, Xiamen 361021, China.
authors: Changjiang
authors: C
authors: Lv
authors: Chungui
authors: C
authors: Zhao
authors: Suping
authors: S
authors: Yang
authors: Yinbo
authors: Y
authors: Qu
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D012244:Rhodospirillaceae / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
chemical_list: D018053:Arsenites; D001426:Bacterial Proteins; C015001:arsenite; D001151:Arsenic