The Chemical Entities of Biological Interest (ChEBI) ontology is downloaded weekly from EMBL-EBI at http://www.ebi.ac.uk/chebi/. The data is made available under the Creative Commons License (CC BY 3.0, http://creativecommons.org/licenses/by/3.0/). For more information see: Degtyarenko et al. (2008) ChEBI: a database and ontology for chemical entities of biological interest. Nucleic Acids Res. 36, D344–D350.
Term:
S. flexneri serotype 2a O-polysaccharide (O factor 9-negative)
A polysaccharide derivative comprised of a [2)-alpha-L-Rhap(III)-(1->2)-alpha-L-Rhap(II)-(1->3)-alpha-L-Rhap(I)-(1->3)-beta-D-GlcpNAc-(1->] tetrasaccharide repeat modified by the (1->4) linkage of an alpha-D-glucosyl group to the Rha(I) residue and by addition of an acetyl group to 50% of the O-6 positions of the GlcNAc residue. The structure provided is representative of that in Shigella flexneri serotype 2a and shows the repeating unit containing the acetyl group on the GlcNAc residue.