睾丸酮丛毛单胞菌JL40中甲酸脱氢酶-O的锑抗性及锑氧化作用

Antimony Resistance and Antimony Oxidation of Formate Dehydrogenase-O in Comamonas testosteroni JL40

利用转座子插入突变技术从睾丸酮丛毛单胞菌(Comamonas testosteroni)JL40中筛选出编码具有锑抗性及锑氧化作用的甲酸脱氢酶-O的fdhO基因。为了进一步验证fdhO基因的功能,在JL40中构建了fdhO基因突变株JL40-fdhO和互补株JL40-fdhO-C,并进行了锑抗性、生长及锑氧化实验。结果表明,fdhO基因突变株的锑抗性及锑氧化速率有所下降,互补株的锑抗性及锑氧化能力得到了一定的恢复。在大肠杆菌中异源表达fdhO基因时发现,与空载对照菌相比,表达fdhO基因的大肠杆菌提高了锑氧化速率。报告基因融合实验表明,fdhO基因的启动子受锑(Ⅲ)的诱导。综上表明,fdhO基因在睾丸酮丛毛单胞菌JL40中具有明显的锑氧化作用,但可能不是唯一的氧化酶;fdhO基因在细菌中的锑氧化功能将会为细菌锑抗性机制的进一步探究提供参考。

We screened gene fdhO coding formate dehydrogenase-O related to antimony resistance and antimony oxidation by transposon insertion mutagenesis from Comamonas testosteroni JL40. In order to verify the function of gene fdhO,we constructed mutant strain JL40-△fdhO and complementary strain JL40-△fdhO-C, and experimentally investigated the antimony resistance, growth, and antimony oxidation. The results showed that the antimony resistance and antimony oxidation rate of mutant strain decreased, and those of complementary strain recovered in a certain degree. Heterologous expression assay in Escherichia coli showed that, Escherichia coli expressing gene fdhO could increase antimony oxidation rate compared with the non-loaded control strain. Moreover,the results of the reporter gene fusion experiment indicated that the promoter of gene fdhO was induced by Sb（ Ⅲ ）. Comprehensive analysis showed that gene fdhO actually had the function of antimony oxidation,but it was not the only oxidase in Comamonas testosteroni JL40. The antimony oxidation function of gene fdhO in bacteria will provide reference for further explore of bacterial antimony resistant mechanism.