Muñoz-Dorado J, Almaula N, Inouye S, Inouye M
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Rutgers, Piscataway 08854.
J Bacteriol. 1993 Feb;175(4):1176-81. doi: 10.1128/jb.175.4.1176-1181.1993.
The nucleoside diphosphate kinase (NDP kinase) from Myxococcus xanthus has been purified to homogeneity and crystallized (J. Munoz-Dorado, M. Inouye, and S. Inouye, J. Biol. Chem. 265:2702-2706, 1990). In the presence of ATP, the NDP kinase was autophosphorylated. Phosphoamino acid analysis was carried out after acid and base hydrolyses of phosphorylated NDP kinase. It was found that the protein was phosphorylated not only at a histidine residue but also at a serine residue. Replacement of histidine 117 with a glutamine residue completely abolished the autophosphorylation and nucleotide-binding activity of the NDP kinase. Since histidine 117 is the only histidine residue that is conserved in all known NDP kinases so far characterized, the results suggest that the phosphohistidine intermediate is formed at this residue during the transphosphorylation reaction from nucleoside triphosphates to nucleoside diphosphates. Preliminary mutational analysis of putative ATP-binding sites is also presented.
黄色粘球菌的核苷二磷酸激酶(NDP激酶)已被纯化至同质并结晶(J. Munoz-Dorado、M. Inouye和S. Inouye,《生物化学杂志》265:2702 - 2706,1990年)。在ATP存在的情况下,NDP激酶发生自身磷酸化。对磷酸化的NDP激酶进行酸碱水解后进行磷酸氨基酸分析。发现该蛋白质不仅在组氨酸残基处磷酸化,而且在丝氨酸残基处也磷酸化。用谷氨酰胺残基替换组氨酸117完全消除了NDP激酶的自身磷酸化和核苷酸结合活性。由于组氨酸117是迄今为止所有已知NDP激酶中唯一保守的组氨酸残基,结果表明在从核苷三磷酸到核苷二磷酸的转磷酸化反应过程中,磷酸组氨酸中间体在该残基处形成。还展示了对假定ATP结合位点的初步突变分析。