beta-D-GlcpA-(1->4)-beta-D-GlcpA-(1->4)-beta-D-Glcp-(1->4)[beta-D-Galp-(1->3)-?-D-Glcp-(1->4)-beta-D-Glcp-(1->4)-beta-D-Glcp-(1->6)]-?-D-Glcp(1->