Perepelov Andrei V, Chen Tingting, Senchenkova Sofya N, Filatov Andrei V, Song Jingjie, Shashkov Alexander S, Liu Bin, Knirel Yuriy A
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, PR China.
Carbohydr Res. 2018 Feb 1;456:1-4. doi: 10.1016/j.carres.2017.11.016. Epub 2017 Dec 2.
The O-specific polysaccharide (O-antigen) is a part of the lipopolysaccharide on the cell surface of Gram-negative bacteria. The O-polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of Escherichia coli O27 and studied by sugar analysis and Smith degradation along with H and C NMR spectroscopy. The following structure of the branched hexasaccharide repeating unit was established, which is unique among known structures of bacterial polysaccharides:where GlcA is non-stoichiometrically O-acetylated at position 3 (∼22%) or 4 (∼37%). Functions of genes in the O-antigen gene cluster of E. coli O27 were tentatively assigned by comparison with sequences in the available databases and found to be consistent with the O-polysaccharide structure.
O-特异性多糖（O抗原）是革兰氏阴性菌细胞表面脂多糖的一部分。通过对大肠杆菌O27脂多糖进行温和酸水解获得O-多糖，并通过糖分析、史密斯降解以及氢和碳核磁共振光谱进行研究。确定了以下分支六糖重复单元的结构，这在已知的细菌多糖结构中是独一无二的：其中葡萄糖醛酸（GlcA）在3位（约22%）或4位（约37%）非化学计量地O-乙酰化。通过与现有数据库中的序列比较，初步确定了大肠杆菌O27的O抗原基因簇中基因的功能，发现与O-多糖结构一致。
