Miallau Linda, Alphey Magnus S, Kemp Lauris E, Leonard Gordon A, McSweeney Sean M, Hecht Stefan, Bacher Adelbert, Eisenreich Wolfgang, Rohdich Felix, Hunter William N
Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.
Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9173-8. doi: 10.1073/pnas.1533425100. Epub 2003 Jul 23.
4-Diphosphocytidyl-2C-methyl-d-erythritol kinase, an essential enzyme in the nonmevalonate pathway of isopentenyl diphosphate and dimethylallyl diphosphate biosynthesis, catalyzes the single ATP-dependent phosphorylation stage affording 4-diphosphocytidyl-2C-methyl-d-erythritol-2-phosphate. The 2-A resolution crystal structure of the Escherichia coli enzyme in a ternary complex with substrate and a nonhydrolyzable ATP analogue reveals the molecular determinants of specificity and catalysis. The enzyme subunit displays the alpha/beta fold characteristic of the galactose kinase/homoserine kinase/mevalonate kinase/phosphomevalonate kinase superfamily, arranged into cofactor and substrate-binding domains with the catalytic center positioned in a deep cleft between domains. Comparisons with related members of this superfamily indicate that the core regions of each domain are conserved, whereas there are significant differences in the substrate-binding pockets. The nonmevalonate pathway is essential in many microbial pathogens and distinct from the mevalonate pathway used by mammals. The high degree of sequence conservation of the enzyme across bacterial species suggests similarities in structure, specificity, and mechanism. Our model therefore provides an accurate template to facilitate the structure-based design of broad-spectrum antimicrobial agents.
4-二磷酸胞苷-2-C-甲基-D-赤藓糖醇激酶是异戊烯基二磷酸和二甲基烯丙基二磷酸生物合成非甲羟戊酸途径中的一种关键酶，催化单一的依赖ATP的磷酸化步骤，生成4-二磷酸胞苷-2-C-甲基-D-赤藓糖醇-2-磷酸。大肠杆菌该酶与底物和一种不可水解的ATP类似物形成的三元复合物的2-A分辨率晶体结构揭示了特异性和催化作用的分子决定因素。该酶亚基呈现出半乳糖激酶/高丝氨酸激酶/甲羟戊酸激酶/磷酸甲羟戊酸激酶超家族特有的α/β折叠，排列成辅因子和底物结合结构域，催化中心位于结构域之间的一个深裂隙中。与该超家族相关成员的比较表明，每个结构域的核心区域是保守的，而底物结合口袋存在显著差异。非甲羟戊酸途径在许多微生物病原体中至关重要，且与哺乳动物使用的甲羟戊酸途径不同。该酶在细菌物种间高度的序列保守性表明其在结构、特异性和机制上具有相似性。因此，我们的模型提供了一个准确的模板，便于基于结构设计广谱抗菌剂。
