ABSTRACT
          
            Gene
            ytkD
            of
            Bacillus subtilis
            , a member of the Nudix hydrolase superfamily, has been cloned and expressed in
            Escherichia coli
            . The purified protein has been characterized as a nucleoside triphosphatase active on all of the canonical ribo- and deoxyribonucleoside triphosphates. Whereas all other nucleoside triphosphatase members of the superfamily release inorganic pyrophosphate and the cognate nucleoside monophosphate, YtkD hydrolyses nucleoside triphosphates in a stepwise fashion through the diphosphate to the monophosphate, releasing two molecules of inorganic orthophosphate. Contrary to a previous report, our enzymological and genetic studies indicate that
            ytkD
            is not an orthologue of
            E. coli mutT
            .
          
 
                                    摘要
          
            
基因
            ytkD
            的
            
基因 ytkD
            是 Nudix
水解酶超家族的成员,已被克隆并在
            大肠杆菌
            .纯化后的蛋白质被鉴定为一种核苷
三磷酸酶,对所有典型的
核糖核苷和脱氧
核糖核苷
三磷酸酶都有活性。该超家族的所有其他核苷
三磷酸酶成员都会释放出无机
焦磷酸和同源的核苷单
磷酸,而 YtkD 则以逐步的方式从二
磷酸水解到单
磷酸,释放出两分子无机正
磷酸盐。与之前的报告相反,我们的酶学和遗传学研究表明
            ytkD
            不是
            大肠杆菌 mutT
            .