tailieunhanh - Báo cáo Y học: Structural studies on the core and the O-polysaccharide repeating unit of Pseudomonas aeruginosa immunotype 1 lipopolysaccharide

The structure of the lipopolysaccharide (LPS) of Pseudomonas aeruginosa immunotype 1 was studied after mild acid and strong alkaline degradations by MS and NMR spectroscopy. Three types of LPS molecules were found, including those with an unsubstituted glycoform 1 core (A) or an isomeric glycoform 2 core substituted with one O-polysaccharide repeating unit (B) or with a long-chain O-polysaccharide. Therefore, of two core glycoforms, only glycoform 2 accepts the O-polysaccharide. LPS molecules, an O-acetyl group is present in the outer core region at unknown position | Eur. J. Biochem. 269 2194-2203 2002 FEBS 2002 doi Structural studies on the core and the O-polysaccharide repeating unit of Pseudomonas aeruginosa immunotype 1 lipopolysaccharide Olga V. Bystrova1 Aleksander S. Shashkov1 Nina A. Kocharova1 Yuriy A Knirel1 Buko Lindner2 Ulrich Zahringer2 and Gerald B. Pier3 1N. D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences Moscow Russia 2Research Center Borstel Center for Medicine and Biosciences Borstel Germany 3Channing Laboratory Department of Medicine Brigham and Women s Hospital Harvard Medical School Boston MA USA The structure of the lipopolysaccharide LPS of Pseudomonas aeruginosa immunotype 1 was studied after mild acid and strong alkaline degradations by MS and NMR spectroscopy. Three types of LPS molecules were found including those with an unsubstituted glycoform 1 core A or an isomeric glycoform 2 core substituted with one O-polysac-charide repeating unit B or with a long-chain O-polysac-charide. Therefore of two core glycoforms only glycoform 2 accepts the O-polysaccharide. a-L-Rha- 1 6 -a-Glc 1 ị 4 LPS molecules an O-acetyl group is present in the outer core region at unknown position. The site and the configuration of the linkage between the O-polysaccharide and the core and the structure of the O-polysaccharide repeating unit were defined in P. aeruginosa immunotype 1. The QuiNAc residue linked to the Rha residue of the core was found to have the b configuration whereas in the interior repeating units of the O-polysac- a-Kdo p p p 2 I II ị 6 2 4 4 a-Glc- 1 6 -P-Glc- 1 3 -a-GalNAla- 1 -A 3 -a-Hep7Cm- 1 3 -a-Hep- 1 5 -a-Kdo- 2 B a-L-Rha- l- 4 -a-GalNAcAN3Ac- l- 4 -a-GalNFoAN- l- 3 -p-QuiNAc- l- 3 -a-L-Rha a-Glc a-Kdo 1 1 p p p 2 ị ị 1 1 3 4 6 2 4 4 a-Glc- 1 6 -0-Glc- 1 - 3 -a-GalNAla- 1 -A 3 -a-Hep7Cm- 1 3 -a-Hep- 1 5 -a-Kdo- 2 In the structures A and B Kdo Hep Hep7Cm GalNAcAN3Ac GalNFoAN QuiNAc GalNAla represent 3-deoxy-D-manno-octulosonic acid .