Bacterial resistance to arsenic compounds
Cervantes, C.
Revista Latinoamericana de Microbiologia 37(4): 387-395
1995
ISSN/ISBN: 0187-4640 PMID: 8900573 Document Number: 449239
Arsenic compounds, often present as environmental pollutants, are highly toxic for most microorganisms. Some microbial strains possess genetic determinants conferring resistance to arsenic derivatives. In bacteria, these determinants are usually located on plasmids, which has facilitated their analysis with molecular detail. Bacterial plasmids conferring arsenic resistance encode specific pumps that extrude arsenite (AsIII). In Gram-negative bacteria, the efflux pump consists of a complex formed by an ATPase (ArsA) associated with a membrane anion channel (ArsB). Arsenate (AsV) is converted to arsenite by a soluble reductase (ArsC). Proteins ArsB and ArsC, but not the ATPase, are also found in Gram-positive bacteria. Besides the widely spread plasmid arsenic resistance determinants, some bacteria possess the ability to enzymatically oxidize arsenite to less toxic arsenate.