STRUCTURES OF THE O-SPECIFIC POLYSACCHARIDE CHAINS OF PECTINATUS-CEREVISIIPHILUS AND PECTINATUS-FRISINGENSIS LIPOPOLYSACCHARIDES

Mild acid hydrolysis of the smooth-type lipopolysaccharide (LPS) of Pe ctinatus frisingensis afforded no polysaccharide but monomeric 6-deoxy -L-altrose (L-6dAIt) which was identified by anion-exchange chromatogr aphy in berate buffer, GLC/MS, H-1-NMR spectroscopy, and optical rotat ion. LPS was degraded with alkali under reductive conditions to give a completely O-deacylated polysaccharide, which was studied by methylat ion 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 heteronuc lear C-13, H-1-COSY, one-dimensional NOE and two-dimensional rotating- frame NOE spectroscopy. It was found that the O-specific polysaccharid e chain of P. frisingensis LPS is a homopolymer of 6-deoxy-L-altrofura nose 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 an d D-fucose, Study of the disaccharide by methylation analysis and alka li-degraded LPS by one-dimensional and two-dimensional H-1-NMR and C-1 3-NMR spectroscopy showed that the O-specific polysaccharide of P. cer evisiiphilus has the following structure: -->2)-beta-D-Fucf-(1-->2)-al pha-D-Glcp-(1-->