Crystal structure of UDP-N-acetylglucosamine enolpyruvyltransferase, the target of the antibiotic fosfomycin
Crystal structure of UDP-N-acetylglucosamine enolpyruvyltransferase, the target of the antibiotic fosfomycin
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DOI：
10.1016/s0969-2126(96)00113-x
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发表时间：
1996-09-15
期刊：
影响因子：
5.7
通讯作者：
Mandelkow, E
中科院分区：
文献类型：
--
作者：
Schonbrunn, E;Sack, S;Mandelkow, E
背景资料：抗生素抗性细菌的数量不断增加，激发了人们对开发新抗生素和其他抗菌剂的兴趣。细菌细胞壁的主要结构元件是杂聚肽聚糖，肽聚糖生物合成的酶是抗菌剂的潜在靶标。一种这样的酶是UDP-N-乙酰葡糖胺烯醇化酰基转移酶（EPT），其催化肽聚糖生物合成中的第一个关键步骤：磷酸烯醇丙酮酸（PEP）的烯醇化酰基部分转移至UDP-N-乙酰葡糖胺（UDPGlcNAc）的3-羟基。结果：在2.0埃分辨率下测定了无底物EPT的晶体结构，其结构显示为一个具有不寻常折叠的双结构域蛋白质（由内而外的α/β桶），该折叠由一个折叠单元的六次重复构成。氨基酸序列中唯一的重复元件是一个短基序，Leu-X（3）-Gly（Ala），它负责折叠单元之间氢键相互作用的形成。催化与EPT类似反应的酶，5-烯醇式莽草酸-3-磷酸合酶（EPSPS），尽管氨基酸序列同一性仅为25%，但具有非常相似的结构。迄今为止，只有这两种酶显示出这种特征性折叠。本结构反映了酶的开放构象，其可能通过两个残基，赖氨酸和精氨酸稳定，带负电荷的UDPGlcNAc与这些残基的结合可以中和两个结构域之间的排斥力，从而允许催化活性的半胱氨酸残基向裂缝移动。
Background: The ever increasing number of antibiotic resistant bacteria has fuelled interest in the development of new antibiotics and other antibacterial agents. The major structural element of the bacterial cell wall is the heteropolymer peptidoglycan and the enzymes of peptidoglycan biosynthesis are potential targets for antibacterial agents. One such enzyme is UDP-N-acetylglucosamine enolpyruvyltransferase (EPT) which catalyzes the first committed step in peptidoglycan biosynthesis: the transfer of the enolpyruvyl moiety of phosphoenolpyruvate (PEP) to the 3-hydroxyl of UDP-N-acetylglucosamine (UDPGlcNAc). EPT is of potential pharmaceutical interest because it is inhibited by the broad spectrum antibiotic fosfomycin.Results: The crystal structure of substrate-free EPT has been determined at 2.0 Angstrom resolution, The structure reveals a two-domain protein with an unusual fold (inside out alpha/beta barrel) which is built up from the sixfold repetition of one folding unit. The only repetitive element in the amino acid sequence is a short motif, Leu-X(3)-Gly(Ala), which is responsible for the formation of hydrogen-bond interactions between the folding units. An enzyme which catalyzes a similar reaction to EPT, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), has a very similar structure despite an amino acid sequence identity of only 25%, To date, only these two enzymes appear to display this characteristic fold.Conclusions: The present structure reflects the open conformation of the enzyme which is probably stabilized through two residues, a lysine and an arginine, located in the cleft between the domains, Binding of the negatively charged UDPGlcNAc to these residues could neutralize the repulsive force between the two domains, thereby allowing the movement of a catalytically active cysteine residue towards the cleft.