Molecular Biogeochemistry Laboratory, Biological & Genetic Resources Institute (BGRI), Hannam University (Jeonmin Campus), 505 Inno-Biz Park, 1646 Yuseong-daero, Yeseong-gu, Daejeon, 34054, Republic of Korea.
Decommissioning Technology Research Division, Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon, 34057, Republic of Korea.
Chemosphere. 2018 Jan;191:729-737. doi: 10.1016/j.chemosphere.2017.10.044. Epub 2017 Oct 19.
ArsH encodes an oxidoreductase, an NAD(P)H-dependent mononucleotide reductase, with an unknown function, frequently within an ars operon, and is widely distributed in bacteria. Novel arsenite-oxidizing bacteria have been isolated from arsenic-contaminated groundwater and surface soil in Vietnam. We found that ArsH gene activity, with arsenite oxidase in the periplasm; it revealed arsenic oxidation potential of the arsH system. Batch experiment results revealed Citrobacter freundii strain VTan4 (DQ481466) and Pseudomonas putida strain VTw33 (DQ481482) completely oxidized 1 mM of arsenite to arsenate within 30-50 h. High concentrations of arsenic were detected in groundwater and surrounding soil obtained from Vinh Tru village in Ha Nam province (groundwater: 11.0 μg/L to 37.0 μg/L; and soil: 2.5 mg/kg, 390.1 mg/kg), respectively. An arsH gene encoding an organoarsenical oxidase protein was observed in arsenite-oxidizing Citrobacter freundii strain VTan4 (DQ481466), whereas arsB, arsH, and arsH were detected in Pseudomonas putida strain VTw33 (DQ481482). arsH gene in bacteria was first reported from Vietnam for resistance and arsenite oxidase. We proposed that residues, Ser 43, Arg 45, Ser 48, and Tyr 49 are required for arsenic binding and activation of arsH. The ars-mediated biotransformation strongly influenced potential arsenite oxidase enzyme of the operon encoding a homogeneous arsH. Results suggest that the further study of arsenite-oxidizing bacteria may lead to a better understanding of arsenite oxidase responses, such as those of arsH, that may be applied to control biochemical properties; for example, speciation, detoxification, bioremediation, biotransformation, and mobilization of arsenic in contaminated groundwater.
ArsH 编码一种氧化还原酶，一种 NAD(P)H 依赖性单核苷酸还原酶，具有未知功能，通常在 Ars 操纵子内，广泛分布于细菌中。从越南受砷污染的地下水和表层土壤中分离到了新型亚砷酸盐氧化细菌。我们发现 ArsH 基因的活性与周质中的亚砷酸盐氧化酶有关；它揭示了 ArsH 系统的砷氧化潜力。批处理实验结果表明，柠檬酸杆菌 VTan4 菌株（DQ481466）和恶臭假单胞菌 VTw33 菌株（DQ481482）在 30-50 小时内将 1mM 的亚砷酸盐完全氧化为砷酸盐。在海阳省 Vinh Tru 村获得的地下水和周围土壤中检测到高浓度的砷（地下水：11.0μg/L 至 37.0μg/L；土壤：2.5mg/kg，390.1mg/kg）。在亚砷酸盐氧化柠檬酸杆菌 VTan4 菌株（DQ481466）中观察到编码有机砷氧化酶蛋白的 ArsH 基因，而在恶臭假单胞菌 VTw33 菌株（DQ481482）中检测到 ArsB、ArsH 和 ArsH。细菌中的 ArsH 基因是首次从越南报道的砷抗性和亚砷酸盐氧化酶。我们提出，残基 Ser 43、Arg 45、Ser 48 和 Tyr 49 是砷结合和 ArsH 激活所必需的。 Ars 介导的生物转化强烈影响编码同质 ArsH 的操纵子中的潜在亚砷酸盐氧化酶。结果表明，进一步研究亚砷酸盐氧化细菌可能有助于更好地理解 ArsH 等亚砷酸盐氧化酶的反应，这些反应可能应用于控制生物化学特性；例如，砷的形态、解毒、生物修复、生物转化和受污染地下水的迁移。
