Borate-Rhamnogalacturonan II Bonding Reinforced by Ca2+ Retains Pectic Polysaccharides in Higher-Plant Cell Walls1

AUTOR(ES)

Kobayashi, Masaru

FONTE

American Society of Plant Physiologists

RESUMO

The extent of in vitro formation of the borate-dimeric-rhamnogalacturonan II (RG-II) complex was stimulated by Ca2+. The complex formed in the presence of Ca2+ was more stable than that without Ca2+. A naturally occurring boron (B)-RG-II complex isolated from radish (Raphanus sativus L. cv Aokubi-daikon) root contained equimolar amounts of Ca2+ and B. Removal of the Ca2+ by trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid induced cleavage of the complex into monomeric RG-II. These data suggest that Ca2+ is a normal component of the B-RG-II complex. Washing the crude cell walls of radish roots with a 1.5% (w/v) sodium dodecyl sulfate solution, pH 6.5, released 98% of the tissue Ca2+ but only 13% of the B and 22% of the pectic polysaccharides. The remaining Ca2+ was associated with RG-II. Extraction of the sodium dodecyl sulfate-washed cell walls with 50 mm trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid, pH 6.5, removed the remaining Ca2+, 78% of B, and 49% of pectic polysaccharides. These results suggest that not only Ca2+ but also borate and Ca2+ cross-linking in the RG-II region retain so-called chelator-soluble pectic polysaccharides in cell walls.

Documentos Relacionados

• Inhibitory Regulation of Higher-Plant Myosin by Ca2+ Ions1
• Two Chains of Rhamnogalacturonan II Are Cross-Linked by Borate-Diol Ester Bonds in Higher Plant Cell Walls.
• The Pore Size of Non-Graminaceous Plant Cell Walls Is Rapidly Decreased by Borate Ester Cross-Linking of the Pectic Polysaccharide Rhamnogalacturonan II1
• Structure of Plant Cell Walls 1: XXVI. The Walls of Suspension-Cultured Sycamore Cells Contain a Family of Rhamnogalacturonan-I-Like Pectic Polysaccharides
• Nearest-neighbor analysis of higher-plant photosystem I holocomplex.