alpha-D-GlcpNAc-(1->4)-?-D-GlcpA-(1->4)-[4)-alpha-D-GlcpNAc-(1->4)-?-D-GlcpA-(1->]n-[4)-alpha-D-GlcpN2,6S2-(1->4)-alpha-L-IdopA2S-(1->]n-alpha-D-GlcpN2,6S2-(1->4)-alpha-L-IdopA2S(1->