b-D-Glucopyranosiduronic acid, (3b,4a)-28-[(O-6-deoxy-a-L-mannopyranosyl-(1®2)-O-[O-b-D-xylopyranosyl-(1®3)-O-b-D-xylopyranosyl-(1®3)-O-b-D-xylopyranosyl-(1®4)-6-deoxy-a-L-mannopyranos