Naumenko Olesya I, Guo Xi, Senchenkova Sof'ya N, Geng Peng, Perepelov Andrei V, Shashkov Alexander S, Liu Bin, Knirel Yuriy A
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Moscow, Russian Federation; Higher Chemical College of the Russian Academy of Sciences, D. I. Mendeleev University of Chemical Technology of Russia, Moscow, Russia.
TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, 300457, Tianjin, PR China.
Carbohydr Res. 2018 Jun 15;462:34-38. doi: 10.1016/j.carres.2018.04.001. Epub 2018 Apr 5.
Mild acid hydrolysis of the lipopolysaccharide of Escherichia coli O54 afforded an O-polysaccharide, which was studied by sugar analysis, solvolysis with anhydrous trifluoroacetic acid, and H and C NMR spectroscopy. Solvolysis cleaved predominantly the linkage of β-d-Ribf and, to a lesser extent, that of β-d-GlcpNAc, whereas the other linkages, including the linkage of α-l-Rhap, were stable under selected conditions (40 °C, 5 h). The following structure of the O-polysaccharide was established: →4)-α-d-GalpA-(1 → 2)-α-l-Rhap-(1 → 2)-β-d-Ribf-(1 → 4)-β-d-Galp-(1 → 3)-β-d-GlcpNAc-(1→ The O-antigen gene cluster of E. coli O54 was analyzed and found to be consistent in general with the O-polysaccharide structure established but there were two exceptions: i) in the cluster, there were genes for phosphoserine phosphatase and serine transferase, which have no apparent role in the O-polysaccharide synthesis, and ii) no ribofuranosyltransferase gene was present in the cluster. Both uncommon features are shared by some other enteric bacteria.
对大肠杆菌O54的脂多糖进行温和酸水解得到一种O-多糖，通过糖分析、用无水三氟乙酸进行溶剂解以及氢和碳核磁共振光谱对其进行了研究。溶剂解主要切断了β-d-核呋喃糖（β-d-Ribf）的连接，在较小程度上切断了β-d-乙酰氨基葡萄糖（β-d-GlcpNAc）的连接，而其他连接，包括α-l-鼠李糖（α-l-Rhap）的连接，在选定条件（40°C，5小时）下是稳定的。确定了O-多糖的以下结构：→4)-α-d-半乳糖醛酸（α-d-GalpA）-(1→2)-α-l-鼠李糖-(1→2)-β-d-核呋喃糖-(1→4)-β-d-半乳糖-(1→3)-β-d-乙酰氨基葡萄糖-(1→。对大肠杆菌O54的O抗原基因簇进行了分析，发现其总体上与所确定的O-多糖结构一致，但有两个例外：i）在该基因簇中，存在磷酸丝氨酸磷酸酶和丝氨酸转移酶的基因，它们在O-多糖合成中没有明显作用；ii）该基因簇中不存在核呋喃糖基转移酶基因。一些其他肠道细菌也具有这两个不常见的特征。
