Ishihara K, Kuramitsu H K
Department of Oral Biology, State University of New York at Buffalo 14214.
Infect Immun. 1995 Apr;63(4):1147-52. doi: 10.1128/iai.63.4.1147-1152.1995.
We have isolated and characterized a neutral phosphatase gene, phoN, from Treponema denticola ATCC 35405. The gene was isolated from a T. denticola clone bank constructed in the medium-copy-number plasmid vector pMCL19. Subcloning and nucleotide sequencing of the DNA insert from one phosphatase clone, pTph14, revealed that the activity corresponded to an open reading frame consisting of 1,027 bp coding for a 37.9-kDa protein. Hydrophobicity analysis indicated that the protein exhibits some hydrophobic regions. Indeed, partial purification of the phosphatase suggested that the enzyme was membrane associated both in T. denticola and in the Escherichia coli clone. The pH optimum of the enzyme, approximately pH 6.4, indicated that it corresponded to a neutral phosphatase activity from T. denticola. An examination of possible natural substrates for the enzyme suggested that this enzyme hydrolyzes nucleoside di- and triphosphates. Northern (RNA) blot analysis revealed that this phosphatase gene is not likely to be present in an operon structure.
我们从齿垢密螺旋体ATCC 35405中分离并鉴定了一个中性磷酸酶基因phoN。该基因是从构建于中拷贝数质粒载体pMCL19中的齿垢密螺旋体克隆文库中分离得到的。对一个磷酸酶克隆pTph14的DNA插入片段进行亚克隆和核苷酸测序后发现，其活性对应于一个由1027 bp组成的开放阅读框，编码一个37.9 kDa的蛋白质。疏水性分析表明该蛋白质具有一些疏水区域。实际上，对该磷酸酶的部分纯化表明，该酶在齿垢密螺旋体和大肠杆菌克隆中均与膜相关。该酶的最适pH约为6.4，表明它对应于齿垢密螺旋体的中性磷酸酶活性。对该酶可能的天然底物进行检测表明，该酶可水解核苷二磷酸和三磷酸。Northern（RNA）印迹分析表明，该磷酸酶基因不太可能存在于操纵子结构中。
