Structure of the O-polysaccharide of Vibriocholerae O43 containing a new monosaccharide derivative, 4-( N-acetyl- l-allothreonyl)amino-4,6-dideoxy- d-glucose

Abstract

The O-polysaccharide of Vibrio cholerae O43 was studied using chemical analyses, triflic acid solvolysis and 2D NMR spectroscopy, including 1H/ 1H COSY, TOCSY, NOESY and 1H/ 13C gradient-selected HSQC experiments. The following structure of the tetrasaccharide repeating unit of the polysaccharide was established: →3)-β- d-Qui p4NAcyl-(1→3)-α- d-Gal pNAcA-(1→4)-α- d-Gal pNAc-(1→3)-α- d-Qui pNAc-(1→ where d-QuiNAc stands for 2-acetamido-2,6-dideoxy- d-glucose, d-Qui4NAcyl for 4-( N-acetyl- l-allothreonyl)amino-4,6-dideoxy- d-glucose and d-GalNAcA for 2-acetamido-2-deoxy- d-galacturonic acid.