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)-α-Rha-(1_3)- β-Gal-(1_2)-α-Rha-(1_4)-β-GlcA-[β-GlcA-(1_4)]-(1_3)-α- Rha-(1_3)-α-Rha-(1_. The absolute configurations for the Rha units are L, while those for the GlcA and Gal residues are D.