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.
A branched polysaccharide derivative composed of a backbone of repeating N-acetyl-beta-D-glucosaminyl-(1->4)-alpha-D-rhamnosyl-(1->3)-alpha-D-rhamnosyl-(1->2)-alpha-D-rhamnosyl-(1->2)-alpha-D-rhamnosyl units, joined by (1->3)-linkages, as shown.