Two Chains of Rhamnogalacturonan II Are Cross-Linked by Borate-Diol Ester Bonds in Higher Plant Cell Walls.
Polysaccharide moiety of the boron-polysaccharide complex (T. Matoh, K. Ishigaki, K. Ohno, J. Azuma [1993] Plant Cell Physiol 34: 639-642) isolated from radish (Raphanus sativus) roots has been shown to be rhamnogalacturonan II by glycosyl-linkage analysis and the presence of diagnostic monosaccharides, including apiose, aceric acid, 2-O-methylfucose, and 3-deoxy-D-manno-2-octulosonic acid. Removal of boron from the complex reduced the molecular weight by one-half without causing a significant increase in the number of reducing end groups, indicating that boron, as boric acid, links two rhamnogalacturonan II chains together to form the boron-polysaccharide complex.
Kobayashi
M.
M
Plant Nutrition Laboratory, Department of Agricultural Chemistry (M.K., T.M.), and Laboratory of Recycle System of Biomass, Department of Bio-environmental Science (J.-i.A.), Faculty of Agriculture, Kyoto University, Kyoto, 606-01, Japan.
Matoh
T.
T
Azuma
Ji.
J