title: Low structural diversity of the O-polysaccharides of Photorhabdus asymbiotica subspp. asymbiotica and australis and their similarity to the O-polysaccharides of taxonomically remote bacteria including Francisella tularensis.
abstract: The O-polysaccharides were isolated from the lipopolysaccharides of emerging human pathogens Photorhabdus asymbiotica subsp. asymbiotica US-86 and US-87 and subsp. australis AU36, AU46, and AU92. Studies by sugar analysis and (1)H and (13)C NMR spectroscopy before and after O-deacetylation showed that the O-polysaccharide structures are essentially identical within, and only slightly different between, the subspecies. The following structures of the repeating units of the O-polysaccharides were established: →3)-β-d-Quip4NGlyFo-(1→4)-α-d-GalpNAcAN3Ac-(1→4)-α-d-GalpNAcA3R-(1→3)-α-d-QuipNAc-(1→ where GalNAcA stands for 2-acetamido-2-deoxygalacturonic acid, GalNAcAN for amide of GalNAcA, QuiNAc for 2-acetamido-2,6-dideoxyglucose, and Qui4NGlyFo for 4,6-dideoxy-4-(N-formylglycyl)aminoglucose; R=Ac in subsp. asymbiotica or H in subsp. australis. The structures established resemble those of a number of taxonomically remote bacteria including Francisella tularensis (Vinogradov, E. V.; Shashkov, A. S.; Knirel, Y. A.; Kochetkov, N. K.; Tochtamysheva, N. V.; Averin, S. P.; Goncharova, O. V.; Khlebnikov, V. S. Carbohydr. Res.1991, 214, 289-297), which differs in (i) the presence of a formyl group on Qui4N rather than the N-formylglycyl group, (ii) the mode of the linkage between the repeating units (β1→2 vs α1→3), (iii) amidation of both GalNAcA residues rather than one residue, and iv) the lack of O-acetylation.
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia. annakond@gmail.com
authors.forename: Anna N
authors.initials: AN
authors.lastname: Kondakova
authors.forename: Nadezhda A
authors.initials: NA
authors.lastname: Kirsheva
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shashkov
authors.forename: Rima Z
authors.initials: RZ
authors.lastname: Shaikhutdinova
authors.forename: Nikolay P
authors.initials: NP
authors.lastname: Arabtsky
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Ivanov
authors.forename: Andrey P
authors.initials: AP
authors.lastname: Anisimov
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Knirel
mesh_terms: D002240:Carbohydrate Sequence; D005604:Francisella tularensis / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019081:O Antigens / Q000737:chemistry*; D020637:Photorhabdus / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*
chemical_list: D008070:Lipopolysaccharides; D019081:O Antigens; D011134:Polysaccharides