An ArsR/SmtB Family Member Is Involved in the Regulation by Arsenic of the Arsenite Oxidase Operon in Thiomonas arsenitoxydans
An ArsR/SmtB Family Member Is Involved in the Regulation by Arsenic of the Arsenite Oxidase Operon in Thiomonas arsenitoxydans
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DOI：
10.1128/aem.01771-14
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发表时间：
2014-10-01
影响因子：
4.4
通讯作者：
Bonnefoy, Violaine
中科院分区：
文献类型：
--
作者：
Moinier, Danielle;Slyemi, Djamila;Bonnefoy, Violaine
编码中度嗜酸兼性自养细菌砷氧硫单胞菌的亚砷酸氧化酶的aioBA操纵子的遗传结构不同于其他亚砷酸盐氧化菌中的aioBA操纵子，因为它编码属于ArsR/SmtB家族的一种金属蛋白AioF。AioF由亚砷酸盐、砷酸盐或锑盐稳定，但不由钼酸盐稳定。砷与AioF紧密结合，很可能是通过半胱氨酸残基。当负载亚砷酸盐或亚砷酸盐时，AioF能够在两个不同的位置与AIO操纵子的调控区域特异结合。在砷氧硫单胞菌中，aioX和aioB的启动子是趋同的，提示存在转录干扰。这些结果表明，砷氧硫单胞菌中的aioBA操纵子的调控比其他含亚砷酸盐氧化菌的aioBA更为复杂，砷结合蛋白AioF参与了这一调控。在这些数据的基础上，提出了一个模型来解释砷对砷氧硫单胞菌中aioBA表达的严格控制。
The genetic organization of the aioBA operon, encoding the arsenite oxidase of the moderately acidophilic and facultative chemoautotrophic bacterium Thiomonas arsenitoxydans, is different from that of the aioBA operon in the other arsenite oxidizers, in that it encodes AioF, a metalloprotein belonging to the ArsR/SmtB family. AioF is stabilized by arsenite, arsenate, or antimonite but not molybdate. Arsenic is tightly attached to AioF, likely by cysteine residues. When loaded with arsenite or arsenate, AioF is able to bind specifically to the regulatory region of the aio operon at two distinct positions. In Thiomonas arsenitoxydans, the promoters of aioX and aioB are convergent, suggesting that transcriptional interference occurs. These results indicate that the regulation of the aioBA operon is more complex in Thiomonas arsenitoxydans than in the other aioBA containing arsenite oxidizers and that the arsenic binding protein AioF is involved in this regulation. On the basis of these data, a model to explain the tight control of aioBA expression by arsenic in Thiomonas arsenitoxydans is proposed.