STRUCTURE OF THE REPEATING OLIGOSACCHARIDE FROM THE LIPOPOLYSACCHARIDE OF THE NITROGEN-FIXING BACTERIUM ACETOBACTER-DIAZOTROPHICUS STRAIN PAL-5

Acetobacter diazotrophicus is an acid-tolerant nitrogen-fixing bacteri um found in roots, rhizosphere, stems, and leaves of sugar cane (Sacch arum officinarum) cultivated in Brazil. The O-polysaccharide from the lipopolysaccharide of the root isolate strain PAL 5 has been determine d by a combination of methylation analysis and two-dimensional high fi eld NMR spectroscopy. The pentasaccharide repeat has the structure. [G RAPHICS] Minor resonances in the NMR spectra are consistent with the p resence of a proportion of repeating units which lack the beta-D-Glc s ide-chain. (C) 1997 Elsevier Science Ltd.