Arsenic methylation by an arsenite S-adenosylmethionine methyltransferase from Spirulina platensis

doi:10.1016/j.jes.2016.06.013

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	Arsenic methylation by an arsenite S-adenosylmethionine methyltransferase from Spirulina platensis
	Yang, Guidi; Ye, Jun; Guo, Yuqing; Xue, Ximei; Yan, Yu; Zhu, Yongguan
刊名	JOURNAL OF ENVIRONMENTAL SCIENCES
	2016-11-01
卷号	49 页码:162-168
关键词	Spirulina Platensis Arsenic Methylation Methyltransferase
DOI	10.1016/j.jes.2016.06.013
英文摘要	Arsenic-contaminated water is a serious hazard for human health. Plankton plays a critical role in the fate and toxicity of arsenic in water by accumulation and biotransformation. Spirulina platensis (S. platensis), a typical plankton, is often used as a supplement or feed for pharmacy and aquiculture, and may introduce arsenic into the food chain, resulting in a risk to human health. However, there are few studies about how S. platensis biotransforms arsenic. In this study, we investigated arsenic biotransformation by S. platensis. When exposed to arsenite (As(III)), S. platensis accumulated arsenic up to 4.1 mg/kg dry weight. After exposure to As(III), arsenate (As(V)) was the predominant species making up 64% to 86% of the total arsenic. Monomethylarsenate (MMA(V)) and dimethylarsenate (DMA(V)) were also detected. An arsenite S-adenosylmethionine methyltransferase from S. platensis (SpArsM) was identified and characterized. SpArsM showed low identity with other reported ArsM enzymes. The Escherichia coli AW3110 bearing SparsM gene resulted in As(III) methylation and conferring resistance to As(III). The in vitro assay showed that SpArsM exhibited As(III) methylation activity. DMA(V) and a small amount of MMA(V) were detected in the reaction system within 0.5 hr. A truncated SpArsM derivative lacking the last 34 residues still had the ability to methylate As(III). The three single mutants of SpArsM (C59S, C186S, and C238S) abolished the capability of As(III) methylation, suggesting the three cysteine residues are involved in catalysis. We propose that SpArsM is responsible for As methylation and detoxification of As(III) and may contribute to As biogeochemistry. (C) 2016 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
内容类型	期刊论文
源URL	[http://ir.rcees.ac.cn/handle/311016/36243]
专题	生态环境研究中心_土壤环境科学实验室
推荐引用方式 GB/T 7714	Yang, Guidi,Ye, Jun,Guo, Yuqing,et al. Arsenic methylation by an arsenite S-adenosylmethionine methyltransferase from Spirulina platensis[J]. JOURNAL OF ENVIRONMENTAL SCIENCES,2016,49:162-168.
APA	Yang, Guidi,Ye, Jun,Guo, Yuqing,Xue, Ximei,Yan, Yu,&Zhu, Yongguan.(2016).Arsenic methylation by an arsenite S-adenosylmethionine methyltransferase from Spirulina platensis.JOURNAL OF ENVIRONMENTAL SCIENCES,49,162-168.
MLA	Yang, Guidi,et al."Arsenic methylation by an arsenite S-adenosylmethionine methyltransferase from Spirulina platensis".JOURNAL OF ENVIRONMENTAL SCIENCES 49(2016):162-168.