title: Linking selenium biogeochemistry to the sulfur-dependent biological detoxification of arsenic.
abstract: Geochemistry often reveals unexpected (anti)correlations. Arsenic (As) and selenium (Se) are cases in point. We explore the hypothesis that bacteria living in an As-replete environment recruited a biological process involving Se and sulfur to fulfil their need for As detoxification. In analogy with the formation of arsenolipids and arsenosugars, which are common non-toxic As metabolites derived from microbial and plant metabolism, we attempt to explain the prevalence of novel sulfur-containing As derivatives, in particular monothioarsenate, in the aqueous environment. Thiolated-As species have been overlooked so far mainly because of the difficulty of their identification. Based on comparative genomics, we propose a scenario where SelD and SelU proteins, commonly used to make selenophosphate and modify transfer RNA, have been recruited to make monothioarsenate, a relatively innocuous arsenical. This hypothesis is discussed in terms of the relative geochemical distribution of Se and As.
authors.affiliation: Ecohydrology, Department of Earth and Environmental Sciences, University of Waterloo, 200 University Ave W, Waterloo, Canada.
authors.forename: Raoul-Marie
authors.initials: RM
authors.lastname: Couture
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Sekowska
authors.forename: Gang
authors.initials: G
authors.lastname: Fang
authors.forename: Antoine
authors.initials: A
authors.lastname: Danchin
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D008658:Inactivation, Metabolic; D008745:Methylation; D010084:Oxidation-Reduction; D012643:Selenium / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D013455:Sulfur; D012643:Selenium; D001151:Arsenic