Structure of the TDP-epi-vancosaminyltransferase GtfA from the chloroeremomycin biosynthetic pathway
Structure of the TDP-epi-vancosaminyltransferase GtfA from the chloroeremomycin biosynthetic pathway
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DOI：
10.1073/pnas.1233577100
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发表时间：
2003-08-05
影响因子：
11.1
通讯作者：
Garavito, RM
中科院分区：
文献类型：
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作者：
Mulichak, AM;Losey, HC;Garavito, RM
在万古霉素类抗生素氯红霉素的生物合成过程中，TDP-表万古胺基转移酶 GtfA 催化来自 TDP 供体的 4-表万古胺连接到糖苷配基共底物的 β-OH-Tyr-6。该途径的糖基转移酶是组合设计有效对抗万古霉素耐药菌株的新型抗生素的潜在工具。这些酶是 GT-B 糖基转移酶超家族的成员，具有同源双域拓扑结构。我们展示了 GtfA 与万古霉素和天然单糖基化肽底物复合物的 2.8 埃晶体结构，代表了密切相关的糖基转移酶之间受体底物结合的首次直接观察。受体底物与 N 末端结构域结合，使得糖苷配基底物的活性羟基氢键与 Ser-10 和 Asp-13 的侧链结合，从而将这些残基鉴定为具有潜在催化重要性的残基。除了酶的开放形式外，晶体结构还揭示了一种封闭形式，其中 TDP 配体结合在域间裂口的供体底物位点上，从而不仅说明了结合相互作用，还说明了酶中伴随底物结合的构象变化。
During the biosynthesis of the vancomycin-class antibiotic chloroeremomycin, TDP-epi-vancosaminyltransferase GtfA catalyzes the attachment of 4-epi-vancosamine from a TDP donor to the beta-OH-Tyr-6 of the aglycone cosubstrate. Glycosyltransferases from this pathway are potential tools for the combinatorial design of new antibiotics that are effective against vancomycin-resistant bacterial strains. These enzymes are members of the GT-B glycosyltransferase superfamily, which share a homologous bidomain topology. We present the 2.8-Angstrom crystal structures of GtfA complexes with vancomycin and the natural monoglycosylated peptide substrate, representing the first direct observation of acceptor substrate binding among closely related glycosyltransferases. The acceptor substrates bind to the N-terminal domain such that the aglycone substrate's reactive hydroxyl group hydrogen bonds to the side chains of Ser-10 and Asp-13, thus identifying these as residues of potential catalytic importance. As well as an open form of the enzyme, the crystal structures have revealed a,closed form in which a TDP ligand is bound at a donor substrate site in the interdomain cleft, thereby illustrating not only binding interactions, but the conformational changes in the enzyme that accompany substrate binding.