alpha-D-GlcpN2,6S23,4Ac2-(1->4)-alpha-L-IdopA2S3Ac-(1->4)-[4)-alpha-D-GlcpN2,6S23Ac-(1->4)-alpha-L-IdopA2S3Ac-(1->]n-alpha-D-GlcpN2,6S23Ac(1->