Colitose-containing O-polysaccharide structure and O-antigen gene cluster of Escherichia albertii HK18069 related to those of Escherichia coli O55 and E. coli O128

• Published in: Carbohydrate research Vol. 480; pp. 73 - 79
• Main Authors: Zheng, Han, Naumenko, Olesya I., Wang, Hong, Xiong, Yanwen, Wang, Jianping, Shashkov, Alexander S., Li, Qun, Knirel, Yuriy A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.07.2019
• Subjects: Bacterial polysaccharide structure; Colitose; Escherichia albertii; Escherichia coli; O-Acetylation; O-antigen gene cluster; O-specific polysaccharide; Bacterial polysaccharide structure; O-Acetylation; O-specific polysaccharide; Escherichia coli; O-antigen gene cluster; Colitose; Escherichia albertii
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2019.05.013

A 3,6-dideoxy-l-xylo-hexose (colitose)-containing partially O-acetylated branched polysaccharide was obtained by mild acid hydrolysis (2% HOAc, 100 °C, 2 h) of the lipopolysaccharide of Escherichia albertii HK18069 followed by gel-permeation chromatography on Sephadex G-50 Superfine. Part of colitose residues (~40%) was cleaved upon hydrolysis, and the full cleavage was achieved by prolonged hydrolysis (8 h) under the same conditions and resulted in a modified linear polysaccharide. Structure of the O-polysaccharide of E. albertii HK18069 was established by 1D and 2D 1H and 13C NMR spectroscopy applied to both initial and modified O-deacetylated and colitose-free polysaccharides:▪ where β-d-Galp is mono-O-acetylated at position either 3 (~50%) or 4 (~30%). The O-antigen gene cluster of E. albertii HK18069 between conserved galF and gnd genes together with flanking regions was sequenced, and predicted functions of the genes were found to be consistent with the O-polysaccharide structure established. The O-polysaccharide structure and the O-antigen gene cluster of E. albertii HK18069 are related to those of Esherichia coli O55 and E. coli O128 reported earlier. It is proposed to create for strain HK18069 a new E. albertii O-serogroup, O8. [Display omitted] •A colitose-containing O-polysaccharide is harbored by E. albertii HK18069 (serotype O8).•Structure of the O-polysaccharide was established by sugar analysis and NMR spectroscopy.•O-antigen gene cluster of E. albertii HK18069 was sequenced and the genes were annotated.•Predicted gene functions are consistent with the O-polysaccharide established.•O-antigen structures and gene clusters of E. albertii O8 and E. coli O55 and O128 are related.