Structure of the β-l-fucopyranosyl phosphate-containing O-specific polysaccharide of Escherichia coli O84

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• 作者：Yuriy A. Knirel^a ; ^{yknirel@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Chengqian Qian^b ; Sofya N. Senchenkova^a ; Xi Guo^b ; Alexander S. Shashkov^a ; Alexander O. Chizhov^a ; Andrei V. Perepelov^a ; Bin Liu^b
• 关键词：6dTal ; 6-deoxytalose ; CID ; collision-induced dissociation ; COSY ; correlation spectroscopy ; DOS ; O-deacetylated OS ; ESI HR MS ; electrospray ionization high-resolution mass spectrometry ; HMBC ; heteronuclear multiple-bond correlation ; HSQC ; heteronuclear single-quantum coherence ; LPS ; lipopolysaccharide ; LPSOH ; O-deacylated LPS ; OS ; a mixture of oligosaccharides ; ROESY ; rotating frame overhauser effect spectroscopy ; TOCSY ; total correlation spectroscopy
• 刊名：International Journal of Biological Macromolecules
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：88
• 期：Complete
• 页码：578-585
• 全文大小：1087 K

文摘

Fine structure of the O-polysaccharide chain of the lipopolysaccharide (O-antigen) defines the serospecificity of bacterial cells, which is the basis for O-serotyping of medically and agriculturally important gram-negative bacteria including Escherichia coli. In order to obtain the O-polysaccharide for structural analysis, the lipopolysaccharide was isolated from cells of E. coli O84a by phenol/water extraction and degraded with mild acid. However, the O-polysaccharide was cleaved at a highly acid-labile β-l-fucopyranosyl phosphate (β-l-Fucp-1-P) linkage to give mainly a pentasaccharide that corresponded to the O-polysaccharide repeat. Therefore, the lipopolysaccharide and the pentasaccharide as well as their O-deacylated derivatives were studied using sugar analysis, NMR spectroscopy, and (for oligosaccharides) ESI HR MS, and the O84-polysaccharide structure was established. The O-polysaccharide is distinguished by the presence of β-l-Fucp-1-P and randomly di-O-acetylated 6-deoxy-d-talose, which are found for the first time in natural carbohydrates. The gene cluster for the O84-antigen biosynthesis was analysed and its content was found to be consistent with the O-polysaccharide structure.