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Linking selenium biogeochemistry to the sulfur‐dependent biological detoxification of arsenic
Author(s) -
Couture RaoulMarie,
Sekowska Agnieszka,
Fang Gang,
Danchin Antoine
Publication year - 2012
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2012.02758.x
Subject(s) - biology , biogeochemistry , detoxification (alternative medicine) , selenium , arsenic , sulfur , environmental chemistry , ecology , alternative medicine , chemistry , medicine , organic chemistry , pathology , materials science , metallurgy
Summary 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.