Structure of a colitose-containing O-specific polysaccharide of the marinebacterium Pseudoalteromonas tetraodonis IAM 14160(T)

O-specific polysaccharide was isolated by mild acid degradation of the lipo polysaccharide of Pseudoalteromonas tetraodonis type strain IAM 14160(T) an d studied by sugar and methylation analyses along with H-1 and C-13 NMR spe ctroscopy, including 2D COSY, TOCSY,H-1,C-13 HMQC and HMBC experiments. The polysaccharide was found to consist of hexasaccharide repeating units cont aining one residue each of D-Gal, D-GlcA, D-GalNAc and D-GlcNAc and two res idues of 3,6-dideoxy-L-xylo-hexose (colitose, Col) and having the following structure: [GRAPHICS] In common with the polysaccharides of some other bacteria, the polysacchari de studied contains a tetrasaccharide fragment alpha -Colp-(1 -->2)-beta -D -Galp-(1 -->3)-[alpha -Colp-(1 -->4)]-beta -D-Galp NAc, which is a colitose ('3-deoxy-L-fucose') analogue of the Lewis(b) blood group antigenic determ inant. (C) 2001 Elsevier Science Ltd. All rights reserved.