Characterization of the physiological substrate for lipopolysaccharide heptosyltransferases I and II
Characterization of the physiological substrate for lipopolysaccharide heptosyltransferases I and II
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DOI：
10.1179/096805101101532828
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Holst, O
中科院分区：
文献类型：
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作者：
Gronow, S;Oertelt, C;Holst, O
L-甘油-D-甘露-七糖是革兰氏阴性菌多种脂多糖核心结构的特征化合物。在大肠杆菌中，已知有两种庚基转移酶，即WAAc和WAAF，它们分别将L-甘油-D-甘露-七糖转移为Re-内毒素和RD(2)-内毒素。有人提出这两个反应都涉及ADPL-甘油-D-甘露-庚糖作为糖供体；然而，这种核苷酸糖的结构从未被完全阐明。在本研究中，从一株庚基转移酶缺陷型大肠杆菌中分离得到了ADPL-甘油-D-甘露-庚糖。经核磁共振波谱和基质辅助激光解吸电离飞行时间质谱仪确定其结构为ADPL-甘油-β-D-甘露-七糖。该化合物代表细菌提取物的唯一成分，该提取物在体外被庚基转移酶I和II接受为糖供体。
L-Glycero-D-manno-heptopyranose is a characteristic compound of many lipopolysaccharide (LPS) core structures of Gram-negative bacteria. In Escherichia coli two heptosyltransferases, namely WaaC and WaaF, are known to transfer L-glycero-D-manno-heptopyranose to Re-LPS and Rd(2)-LPS, respectively. It had been proposed that both reactions involve ADPL-glycero-D-manno-heptose as a sugar donor; however, the structure of this nucleotide sugar had never been completely elucidated. In the present study, ADPL-glycero-D-manno-heptose was isolated from a heptosyltransferase-deficient E. coli mutant. and its structure was determined by nuclear magnetic resonance spectroscopy and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry as ADPL-glycero-beta -D-manno-heptopyranose. This compound represented the sole constituent of the bacterial extract that was accepted as a sugar donor by heptosyltransferases I and II in vitro.