Determination of the Structure and Conformation of Bacterial Polysaccharides by Carbon 13 Nuclear Magnetic Resonance

The application of carbon 13 nuclear magnetic resonance to analysis of some phosphorylated acetamidohexose-containing meningococcal polysaccharides is described. A complete assignment of the spectra of both the serogroup A and X polysaccharides has been made. In addition the spectrum of a structurally related 1+6-a-linked 2-acetamido-Zdeoxy-n-glucose phosphate polysaccharide from Slaphylococcus Zacfis NCTC 2102 has also been completely assigned. This has resulted in the structural elucidation of the serogroup X polysaccharide as a homopolymer of 2-acetamido-2deoxy-D-glucopyranose, linked by 1 -A-a-phosphodiester bonds. In addition, the 0-acetyl substituents of the serogroup A polysaccharide have been located at C-3 of approximately 70% of the repeating units (1 id-a-linked 2-acetamido-2-deoxy-n-mannopyranose phosphate) of the homopolymer. Preliminary conformational information was also obtained from the large three-bond couplings between 31P and W (3531,.&, indicative of highly extended backbone formations.