Structure of the iron-binding exopolysaccharide produced anaerobically by the gram-negative bacterium Klebsiella oxytoca BAS-10

Klebsiella oxytoca BAS-10 is a Gram-negative micro-organism capable of growing on high concentrations of heavy metals. This bacterium produces large amounts of an iron-binding exopolysaccharide that, in the presence of metallic cations, precipitates as a dense gel. The primary and secondary structure of the repeating unit of such polysaccharide has been characterised by chemical and spectroscopic methods, resulting in the following heptasaccharide: 2)-alpha-Rha-(1 -> 3)beta-Gal-(1 -> 2)-alpha-Rha-(1 -> 4)-beta-GlcA-[beta-GlcA-(1 -> 4)]-(1 -> 3)-alpha-Rha-(l -> 3)-alpha-Rha-(l ->. The absolute configurations for the Rha units are L, while those for the GlcA and Gal residues are D. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).