Structure of the 4-O-[1-Carboxyethyl]-d-Mannose-Containing O-Specific Polysaccharide of a Halophilic Bacterium sp. EG9S8QL.

The moderately halophilic strain sp. EG9S8QL was isolated among 11 halophilic strains from saline mud (Emisal Salt Company, Lake Qarun, Fayoum, Egypt). The lipopolysaccharide was extracted from dried cells of sp. EG9S8QL by the phenol-water procedure. The OPS was obtained by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with H and C NMR spectroscopy, including H,H COSY, TOCSY, ROESY, H,C HSQC, and HMBC experiments. The OPS was found to be composed of linear tetrasaccharide repeating units of the following structure: →2)-β-Man4Lac-(1→3)-α-ManNAc-(1→3)-β-Rha-(1→4)-α-GlcNAc-(1→, where Man4Lac is 4-O-[1-carboxyethyl]mannose.