?-D-GlcpNAc-(1->?)-?-D-GlcpA-(1->?)-?-D-GlcpNAc-(1->?)-?-D-GlcpA-(1->?)-?-D-GlcpNAc-(1->?)-?-D-GlcpA-(1->?)-?-D-GlcpNAc-(1->?)-?-D-GlcpA-(1->?)-?-D-GlcpNAc-(1->?)-?-D-GlcpA-(1->?)-D-GlcNAc(?->