Structure of the Escherichia coli heptosyltransferase WaaC:: Binary complexes with ADP AND ADP-2-deoxy-2-fluoro heptose
Structure of the Escherichia coli heptosyltransferase WaaC:: Binary complexes with ADP AND ADP-2-deoxy-2-fluoro heptose
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DOI：
10.1016/j.jmb.2006.07.057
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发表时间：
2006-10-20
影响因子：
5.6
通讯作者：
Ducruix, Arnaud
中科院分区：
文献类型：
--
作者：
Grizot, Sylvestre;Salem, Michele;Ducruix, Arnaud
脂多糖构成革兰氏阴性菌外膜的外小叶，因此对细胞生长和活力至关重要。庚糖基转移酶WaaC是参与LPS内核区合成的糖基转移酶（GT）。催化第一个L-甘油-D-甘露-庚糖（庚糖）分子加成至Kdo（2）-脂质A分子的一个3-脱氧-D-甘露-辛-2-酮糖酸（Kdo）残基。庚糖是LPS核心结构域的必需组分;其缺失导致与深粗糙表型相关的截短脂多糖，从而导致对抗生素的更大敏感性和对致病性革兰氏阴性菌的毒力减弱。因此，WaaC代表了抗菌药物设计中有前途的靶标。在这里，我们报告的结构WaaC从大肠杆菌致病菌株RS 218单独在1.9埃分辨率，并在复杂的ADP或不可裂解的类似物ADP-2-脱氧-2-氟-庚糖的糖供体在2.4埃分辨率。WaaC在两个结构域中采用GT-B折叠，这是一个糖基转移酶结构超家族的特征。三种不同结构的比较表明，WaaC不进行域旋转，特征的GT-B家族，底物结合后，但允许底物类似物和反应产物，以采取显着不同的构象内的活性位点。此外，这两个二元复合物提供了一个近距离的供体亚位点，并与定点诱变研究的结果一起，提供了催化机制的模型的证据。(c)2006年由Elsevier Ltd.出版
Lipopolysaccharides constitute the outer leaflet of the outer membrane of Gram-negative bacteria and are therefore essential for cell growth and viability. The heptosyltransferase WaaC is a glycosyltransferase (GT) involved in the synthesis of the inner core region of LPS. It catalyzes the addition of the first L-glycero-D-manno-heptose (heptose) molecule to one 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) residue of the Kdo(2)-lipid A molecule. Heptose is an essential component of the LPS core domain; its absence results in a truncated lipopolysaccharide associated with the deep-rough phenotype causing a greater susceptibility to antibiotic and an attenuated virulence for pathogenic Gram-negative bacteria. Thus, WaaC represents a promising target in antibacterial drug design. Here, we report the structure of WaaC from the Escherichia coli pathogenic strain RS218 alone at 1.9 angstrom resolution, and in complex with either ADP or the non-cleavable analog ADP-2-deoxy-2-fluoro-heptose of the sugar donor at 2.4 angstrom resolution. WaaC adopts the GT-B fold in two domains, characteristic of one glycosyltransferase structural superfamily. The comparison of the three different structures shows that WaaC does not undergo a domain rotation, characteristic of the GT-B family, upon substrate binding, but allows the substrate analog and the reaction product to adopt remarkably distinct conformations inside the active site. In addition, both binary complexes offer a close view of the donor subsite and, together with results from site-directed mutagenesis studies, provide evidence for a model of the catalytic mechanism. (c) 2006 Published by Elsevier Ltd.