Linking selenium biogeochemistry to the sulfur-dependent biological detoxification of arsenic

Environ Microbiol. 2012 Jul;14(7):1612-23. doi: 10.1111/j.1462-2920.2012.02758.x. Epub 2012 Apr 20.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Arsenic / metabolism*
  • Bacteria / genetics
  • Bacteria / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Inactivation, Metabolic
  • Methylation
  • Oxidation-Reduction
  • Selenium / chemistry*
  • Sulfur / chemistry*


  • Bacterial Proteins
  • Sulfur
  • Selenium
  • Arsenic