Pal Siddhartha, Sengupta Kriti
National Centre for Cell Science, Ganeshkhind, Pune, 411007, India.
Bioenergy Group, Agharkar Research Institute, Gopal Ganesh Agarkar Road, Pune, 411004, India.
J Genet Eng Biotechnol. 2021 Mar 29;19(1):47. doi: 10.1186/s43141-021-00146-x.
Arsenite oxidase (EC 1.20.2.1) is a metalloenzyme that catalyzes the oxidation of arsenite into lesser toxic arsenate. In this study, 78 amino acid sequences of arsenite oxidase from unculturable bacteria available in metagenomic data of arsenic-contaminated soil have been characterized by using standard bioinformatics tools to investigate its phylogenetic relationships, three-dimensional structure and functional parameters.
The phylogenetic relationship of all arsenite oxidase from unculturable microorganisms was revealed their closeness to bacterial order Rhizobiales. The higher aliphatic content showed that these enzymes are thermostable and could be used for in situ bioremediation. A representative protein from each phylogenetic cluster was analysed for secondary structure arrangements which indicated the presence of α-helices (~63%), β-sheets (57-60%) and turns (13-15%). The validated 3D models suggested that these proteins are hetero-dimeric with two chains whereas alpha chain is the main catalytic subunit which binds with arsenic oxides. Three representative protein models were deposited in Protein Model Database. The query enzymes were predicted with two conserved motifs, one is Rieske 3Fe-4S and the other is molybdopterin protein.
Computational analysis of protein interactome revealed the protein partners might be involved in the whole process of arsenic detoxification by Rhizobiales. The overall report is unique to the best of our knowledge, and the importance of this study is to understand the theoretical aspects of the structure and functions of arsenite oxidase in unculturable bacteria residing in arsenic-contaminated sites.
亚砷酸盐氧化酶（EC 1.20.2.1）是一种金属酶，可催化亚砷酸盐氧化为毒性较小的砷酸盐。在本研究中，利用标准生物信息学工具对砷污染土壤宏基因组数据中不可培养细菌的78个亚砷酸盐氧化酶氨基酸序列进行了表征，以研究其系统发育关系、三维结构和功能参数。
揭示了所有不可培养微生物的亚砷酸盐氧化酶与根瘤菌目细菌的系统发育关系密切。较高的脂肪族含量表明这些酶具有热稳定性，可用于原位生物修复。对每个系统发育簇中的代表性蛋白质进行了二级结构分析，结果表明存在α-螺旋（约63%）、β-折叠（57-60%）和转角（13-15%）。经过验证的三维模型表明，这些蛋白质是由两条链组成的异源二聚体，而α链是与氧化砷结合的主要催化亚基。三个代表性蛋白质模型已存入蛋白质模型数据库。预测查询的酶有两个保守基序，一个是Rieske 3Fe-4S，另一个是钼蝶呤蛋白。
蛋白质相互作用组的计算分析表明，蛋白质伙伴可能参与了根瘤菌目细菌砷解毒的全过程。据我们所知，总体报告具有独特性，本研究的重要性在于了解砷污染位点中不可培养细菌中亚砷酸盐氧化酶结构和功能的理论方面。
