Abstract Dechlorination is the key step in biological degradation of dichloromethane (DCM), which is catalyzed by the enzyme DCM dehalogenase. In this study, the detailed structure and function of DCM dehalogenase in Methylobacterium rhodesianum H13 were investigated. Our results indicate that DCM dehalogenase (C1505H2255N403O430S7) is a stable hydrophilic protein localized in the cytoplasm, with an isoelectric point of 6.35. They also indicate that DCM dehalogenase is a frizzled protein with 52.43% of amino acid residues exposed on its surface, and that alpha-helices are a main structural component (53.47%). As one of the theta class glutathione S-transferases (GSTs), DCM dehalogenase presents as a dimeric structure and shows strong substrate selectivity. The catalytic tunnel radius and length of DCM dehalogenase are both 1.4 Å. Glu42 and Val43 are two of the essential amino acids in both the catalytic tunnel and catalytic pockets. The amino acid sequence of DCM dehalogenase was predicted to be homologous among various microorganisms, and its active site was conserved with eight potential sites. The recombinant DCM dehalogenase was expressed in E. coli BL21 strain. The optimum conditions for DCM dehalogenase are pH 8, temperature of 30 °C and presence of Mn2+. All the obtained information of DCM dehalogenase will lay the foundation for further study of its structural transformation and functional improvement.

中文翻译：

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罗得西亚甲基杆菌 H13 二氯甲烷脱卤酶的生物信息学、细菌表达和酶活性分析

摘要 脱氯是二氯甲烷(DCM)生物降解的关键步骤，由DCM脱卤酶催化。在这项研究中，研究了 DCM 脱卤酶在罗得西亚甲基杆菌 H13 中的详细结构和功能。我们的结果表明 DCM 脱卤酶 (C1505H2255N403O430S7) 是一种稳定的亲水蛋白，位于细胞质中，等电点为 6.35。他们还表明 DCM 脱卤酶是一种卷曲蛋白，52.43% 的氨基酸残基暴露在其表面，α 螺旋是主要结构成分 (53.47%)。作为 theta 类谷胱甘肽 S-转移酶 (GST) 之一，DCM 脱卤酶呈现为二聚体结构并显示出很强的底物选择性。DCM 脱卤酶的催化隧道半径和长度均为 1.4 Å。Glu42 和 Val43 是催化隧道和催化口袋中的两种必需氨基酸。DCM脱卤酶的氨基酸序列预计在各种微生物中具有同源性，其活性位点保守，有8个潜在位点。重组DCM脱卤酶在大肠杆菌BL21菌株中表达。DCM 脱卤酶的最佳条件是 pH 8、温度 30 °C 和 Mn2+ 的存在。所有获得的DCM脱卤酶信息将为进一步研究其结构转化和功能改进奠定基础。重组DCM脱卤酶在大肠杆菌BL21菌株中表达。DCM 脱卤酶的最佳条件是 pH 8、温度 30 °C 和 Mn2+ 的存在。所有获得的DCM脱卤酶信息将为进一步研究其结构转化和功能改进奠定基础。重组DCM脱卤酶在大肠杆菌BL21菌株中表达。DCM 脱卤酶的最佳条件是 pH 8、温度 30 °C 和 Mn2+ 的存在。所有获得的DCM脱卤酶信息将为进一步研究其结构转化和功能改进奠定基础。