title: Structural studies of the O-specific polysaccharide from the lipopolysaccharide of Mesorhizobium huakuii strain S-52, the symbiotic partner of Astragalus sinicus.
abstract: The O-specific polysaccharide (OPS) obtained by mild-acid degradation of the lipopolysaccharide isolated from Mesorhizobium huakuii strain S-52 was studied by sugar and ethylation analyses along with (1)H and (13)C NMR spectroscopy. It was concluded that the OPS was composed of trisaccharide repeating units containing two residues of 6-deoxy-l-talose (6dTal) and one l-rhamnose (Rha), whose sequence in the OPS was determined by NOESY and HMBC experiments. The minor 3-O-acetylation (about 10%) of 6-deoxytalose glycosidically substituted at position-2 was judged by relative signal intensities of corresponding O-acetylated and non-acetylated 6dTal residues. Moreover, it was found that the non-reducing end of the OPS repeating unit was occupied by 3-O-methyl-d-fucose, which terminated the O-chain as a cap-residue. These data defined the structure of the OPS as: α-3-OMe-d-Fucp-(1→[2)-α-l-6dTalp-(1→3)-α-l-6dTalp-(1→2)-α-l-Rhap-(1→](n).
authors.affiliation: Department of Genetics and Microbiology, Maria Curie-Sklodowska University, 19 Akademicka St., 20-033 Lublin, Poland. aturska@hektor.umcs.lublin.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Turska-Szewczuk
authors.forename: Ryszard
authors.initials: R
authors.lastname: Russa
mesh_terms: D020561:Alphaproteobacteria / Q000737:chemistry*; D027883:Astragalus Plant; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019081:O Antigens / Q000737:chemistry*; D013559:Symbiosis
chemical_list: D019081:O Antigens