Structures of the o-specific polysaccharide chains of pectinatus cerevisiiphilus and pectinatus frisingensis lipopolysaccharides

Abstract

Mild acid hydrolysis of the smooth-type lipopolysaccharide (LPS) of Pectinatus frisingensis afforded no polysaccharide but monomeric 6-deoxy-L-altrose (L-6dAIt) which was identified by anion-exchange chromatography in berate buffer, GLC/MS, H-1-NMR spectroscopy, and optical rotation. LPS was degraded with alkali under reductive conditions to give a completely O-deacylated polysaccharide, which was studied by methylation analysis, H-1-NMR and C-13-NMR spectroscopy, including sequential, selective spin-decoupling, two-dimensional correlation spectroscopy (COSY), COSY with relayed coherence transfer, two-dimensional heteronuclear C-13, H-1-COSY, one-dimensional NOE and two-dimensional rotating-frame NOE spectroscopy. It was found that the O-specific polysaccharide chain of P. frisingensis LPS is a homopolymer of 6-deoxy-L-altrofuranose built up of tetrasaccharide-repeating units having the following structure: [GRAPHICS] Similarly, mild acid degradation of smooth-type LPS of Pectinatus cerevisiiphilus resulted in depolymerisation of the polysaccharide chain to give a disaccharide consisting of D-glucose and D-fucose, Study of the disaccharide by methylation analysis and alkali-degraded LPS by one-dimensional and two-dimensional H-1-NMR and C-13-NMR spectroscopy showed that the O-specific polysaccharide of P. cerevisiiphilus has the following structure: -->2)-beta-D-Fucf-(1-->2)-alpha-D-Glcp-(1-->