Organoarsenical Biotransformations by Shewanella putrefaciens.
Organoarsenical Biotransformations by Shewanella putrefaciens.
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DOI：
10.1021/acs.est.6b00235
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发表时间：
2016-08-02
影响因子：
11.4
通讯作者：
Rosen BP
中科院分区：
文献类型：
--
作者：
Chen J;Rosen BP
微生物在全球砷循环中起着关键作用。无机砷在细菌和古菌中的氧化还原循环是目前研究的热点。有机砷的生物转化的平行循环不太好的特点。在这里，我们描述了有机砷在环境微生物腐败希瓦氏菌的生物转化。在好氧生长条件下，S.腐败菌将除草剂MSMA（甲基胂酸盐或MAs（V））还原为甲基胂酸盐（MAs（III））。尽管它不含编码ArsI C-As裂解酶的arsI基因，但S.腐败菌将MA（III）去甲基化为As（III）。它能裂解芳香族砷化合物中的C-As键，如三价形式的抗微生物剂洛克沙胂（Rox（III））、硝砷胂（Nit（III））和苯砷（PhAs-（III）），这些化合物被用作家禽和猪的生长促进剂。S.腐殖菌硫醇化甲基化砷，将MAs（V）转化为毒性更大的代谢物一甲基硫代砷酸盐（MMMTAs（V）），并将二甲基砷酸盐（DMAs（V））转化为二甲基硫代砷酸盐（DMMTAs（V））。它还还原Nit（V）的硝基，形成对氨基苯砷酸盐（p-arsanilic acid或p-AsA（V）），和Rox（III），形成3-氨基-4-羟基苄基胂酸盐（3A 4 HBzAs（V））。阐明了有机砷的生物转化S。腐败菌提供了这些环境污染物是如何降解的整体评价。
Microbes play a critical role in the global arsenic biogeocycle. Most studies have focused on redox cycling of inorganic arsenic in bacteria and archaea. The parallel cycles of organoarsenical biotransformations are less well characterized. Here we describe organoarsenical biotransformations in the environmental microbe Shewanella putrefaciens. Under aerobic growth conditions, S. putrefaciens reduced the herbicide MSMA (methylarsenate or MAs(V)) to methylarsenite (MAs(III)). Even though it does not contain an arsI gene, which encodes the ArsI C–As lyase, S. putrefaciens demethylated MAs(III) to As(III). It cleaved the C–As bond in aromatic arsenicals such as the trivalent forms of the antimicrobial agents roxarsone (Rox(III)), nitarsone (Nit(III)) and phenylarsenite (PhAs-(III)), which have been used as growth promoters for poultry and swine. S. putrefaciens thiolated methylated arsenicals, converting MAs(V) into the more toxic metabolite monomethyl monothioarsenate (MMMTAs(V)), and transformed dimethylarsenate (DMAs(V)) into dimethylmonothioarsenate (DMMTAs(V)). It also reduced the nitro groups of Nit(V), forming p-aminophenyl arsenate (p-arsanilic acid or p-AsA(V)), and Rox(III), forming 3-amino-4-hydroxybenzylarsonate (3A4HBzAs(V)). Elucidation of organoarsenical biotransformations by S. putrefaciens provides a holistic appreciation of how these environmental pollutants are degraded.