Elucidation of the O-antigen structure of Escherichia coli O93 and characterization of its biosynthetic genes

• DOI: 10.1093/glycob/cwac069
• Publication Date: 2022-10-14T12:16:35Z
• Authors: Axel Furevi; Jonas Ståhle; Claudio Muheim; Spyridon Gkotzis; Daniel O Daley; Klas I Udekwu; Göran Widmalm
• Keywords: Characterization; Escherichia

Abstract The structure of the O-antigen from international reference strain Escherichia coli O93:−:H16 has been determined. A nonrandom modal chain-length distribution was observed for lipopolysaccharide, a pattern which is typical when long O-specific polysaccharides are expressed. By combination (i) bioinformatics information on gene cluster related to synthesis including putative function glycosyl transferases, (ii) magnitude NMR coupling constants anomeric protons, and (iii) unassigned 2D 1H, 13C-HSQC, 1H,1H-TOCSY spectra it possible efficiently elucidate carbohydrate polymer in an automated fashion using computer program CASPER. polysaccharide also carries O-acetyl groups their locations were determined by experiments showing that ~½ population 2,6-di-O-acetylated, ~¼ 2-O-acetylated, whereas did not carry group(s) 3-O-substituted mannosyl residue repeating unit. tetrasaccharide unit given by: →2)-β-d-Manp-(1→3)-β-d-Manp2Ac6Ac-(1→4)-β-d-GlcpA-(1→3)-α-d-GlcpNAc-(1→, should be biological shares structural elements with capsular E. K84 K50. acidic Cellulophaga baltica NN015840T differs O93 lacking group at O6 O-acetylated residue.