[alpha-D-GlcpA-(1->2)-beta-D-Xylp-(1->4)-[alpha-L-Araf-(1->3)-beta-D-Xylp-(1->4)]-alpha-L-Araf-(1->2)-alpha-L-Araf-(1->3)-beta-D-Xylp-(1->4)]-?-D-Xylp(1->