Structure of an extracellular polysaccharide produced by Erwinia chrysanthemi

Erwinia chrysanthemi pv zeae strain SR260, a phytopathogen of corn, produced from lactose an acidic extracellular polysaccharide which was purified and found to consist Of L-rhamnose, D-mannose, D-glucose, and D-glucuronic acid in the ratio of 3:1:1:1. A combination of chemical (carboxyl-group reduction, methylation analysis, periodate oxidation, Smith degradation, and lithium-ethylenediamine degradation) and physical (1 and 2D NMR spectroscopy) methods revealed that the polysaccharide is composed of a hexasaccharide repeating unit 1: [GR