State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
Environ Sci Technol. 2020 Nov 3;54(21):14107-14113. doi: 10.1021/acs.est.0c03875. Epub 2020 Oct 15.
Microbial antimonate [Sb(V)] respiratory reduction is an important process regulating Sb redox transformation in the environment. However, little is known about the microbial respiratory reductase for Sb(V). Herein, we report Sb(V)-respiring reduction by sp. ANA-3 through an arsenate respiratory reductase encoded by . Incubation experiments showed that sp. ANA-3 mediated Sb(V)-respiring reduction, which was dependent on the cell concentration. Both protein analysis and reverse transcriptase-polymerase chain reaction results revealed that was highly expressed in Sb(V)-respiring reduction. In vivo evidence with mutants indicated that neither ANA-3-Δ nor ANA-3-Δ was capable of reducing Sb(V) as efficiently as the wild type, whereas complementation by the wild-type sequences of and rescued the mutants' ability. Our in vitro results showed that ArrAB purified by His-Tag was able to mediate Sb(V) reduction, though with much suppressed catalytic kinetics compared with As(V) reduction. The cell-concentration-dependent reduction of Sb(V) was regulated by quorum sensing via the gene. This study opens a new chapter in the mechanistic understanding of microbial Sb(V) respiratory reduction.
微生物对锑酸盐 [Sb(V)] 的呼吸还原作用是调节环境中 Sb 氧化还原转化的重要过程。然而，对于 Sb(V)的微生物呼吸还原酶知之甚少。本文通过砷酸盐呼吸还原酶编码基因 报道了 sp.ANA-3 对 Sb(V)的呼吸还原作用。孵育实验表明， sp.ANA-3 通过依赖细胞浓度的方式介导 Sb(V)的呼吸还原。蛋白分析和逆转录聚合酶链式反应结果表明， 在 Sb(V)呼吸还原过程中高度表达。通过突变体的体内证据表明，与野生型相比， ANA-3-Δ 或 ANA-3-Δ 都不能有效地还原 Sb(V)，而通过野生型序列的互补 和 则挽救了突变体的能力。我们的体外结果表明，通过 His-Tag 纯化的 ArrAB 能够介导 Sb(V)还原，尽管与 As(V)还原相比，其催化动力学受到很大抑制。通过 基因的群体感应调节细胞浓度依赖性 Sb(V)还原。这项研究为微生物 Sb(V)呼吸还原的机制理解开辟了新的篇章。
