New and novel pathways of arsenic uptake and transformation
This presentation will focus on recent progress on the mechanisms of metalloid uptake, metabolism, and detoxification in bacteria, archaea and eukaryotic microbes. One of the initial challenges of the earliest cells would have been the ability to detoxify heavy metal ions, transition metal ions and metalloids, including arsenic and antimony. The presence of arsenic resistance (ars) genes in the genome of by far most living organism sequenced to date illustrates firstly that ars genes must be ancient and secondly that arsenic is still ubiquitous in the environment, providing the selective pressure that maintains them in present day organisms. Some early cells also probably could use arsenite as an electron acceptor, giving selective pressure for the evolution of respiratory arsenate reductase. As atmospheric O2 levels increased, arsenite was oxidized to arsenate abiotically. This provided an advantage for the evolution of arsenate reductases, some for arsenate respiration and energy production, and others for arsenate detoxification. Present day selective pressure for metalloid resistance also comes from sources such as natural release of arsenic from volcanic activities, mining activities, the burning of coal and other human activities. Thus, an understanding of the molecular details of metalloid transport systems and modifying enzymes is essential for understanding how the environment affects microbial evolution and how microorganisms modify the environment. In addition, knowledge of pathways of uptake and detoxifieation is also important for genetically engineering organisms capable of bio (phyto) remediation. This presentation will focus on our recent identification of novel enzymes for arsenic reduction, oxidation and methylation that expand the possibilities for metalloid metabolism and transformations.
Arsenite uptake arsenate reductase arsenite S-adenosylmethyltransferase
Barry P. Rosen
Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit, MI 48201
国际会议
第九届痕量元素生物地球化学国际会议(9th International Conference on the Biogeochemistry of Trace Elements)
北京
英文
871-872
2007-07-15（万方平台首次上网日期，不代表论文的发表时间）