resumo
With the intent of contributing to a carbohydrate-based vaccine against the gastroduodenal pathogen, Helicobacter pylori, we report here the structure of cell-surface mannans obtained from a virulent strain. Unlike other wild-type strains, this strain was found to express in good quantities this polysaccharide in vitro. Structural analysis revealed a branched mannan formed by a backbone of alpha-(1 -> 6)-linked mannopyranosyl residues with approximately 80% branching at the O-2 position. The branches were composed of O-2-linked Man residues in both alpha- and beta-configurations: ->[6)-alpha-D-Manp-(1 -> 6](n)-alpha-D-Manp-(1 -> 6 R1 -> 2 R = alpha-D-Man; ->[2)-alpha-D-Man-(1](n)-> 2)-alpha-D-Man; ->[2)-alpha-D-Man-(1]n ->? In addition, this strain also expressed cell-surface emblematic H. pylori lipopolysaccharides (LPS) containing partially fucosylated polyLacNAc O-chains. Affinity assays with polymyxin-B and concanavalin A revealed no association between the mannan and the LPS. The described mannans may be implicated in the mediation of host-microbial interactions and immunological modulation. (C) 2010 Elsevier Ltd. All rights reserved.
palavras-chave
MANNOSE-BINDING LECTIN; NUCLEAR-MAGNETIC-RESONANCE; O-SPECIFIC POLYSACCHARIDE; STRUCTURAL-ANALYSIS; WALL MANNAN; BIOPSY SPECIMENS; LIPOPOLYSACCHARIDES; ANTIGEN; YEAST; GENE
categoria
Biochemistry & Molecular Biology; Chemistry
autores
Ferreira, JA; Azevedo, NF; Vieira, MJ; Figueiredo, C; Goodfellow, BJ; Monteiro, MA; Coimbra, MA
nossos autores
Brian James Goodfellow
Professor Auxiliaragradecimentos
This work was supported by Fundacao para a Ciencia e Tecnologia (FCT) through project Pylori E&LPS POCI/QUI/56393/2004, PhD grant SFRH/BD/19929/2004, by the Natural Sciences and Engineering Research Council of Canada (NSERC), and by the European Network of Research Infrastructures within the 6th Framework Programme of the EC (Contract # RII3-026145, EU-NMR). The authors further thank Dr. Adrien Favier (RALF-NMR facility, Grenoble - France) for conducting NMR experiments.