Structure of plant cell walls
- Univ. of Georgia, Athens (USA)
Considerable information has been obtained about the primary structures of suspension-cultured sycamore (Acer pseudoplatanus) cell-wall pectic polysaccharides, i.e. rhamnogalacturonan l, rhamnogalacturonan ll, and homogalacturonan. However, these polysaccharides, which are solubilized from the walls by endo-{alpha}-1,4-polygalacturonase, account for only about half of the pectic polysaccharides known to be present in sycamore cell walls. We now report that, after exhaustive treatment with endo-{alpha}-1,4-polygalacturonase, additional pectic polysaccharides were extracted from sycamore cell walls by treatment with Na{sub 2}CO{sub 3} at 1 and 22{degree}C. These previously uncharacterized polysaccharides accounted for {approximately}4% of the cell wall. Based on the glycosyl and glycosyl-linkage compositions and the nature of the products obtained by treating the quantitatively predominant NaCO{sub 3}-extracted polysaccharides with lithium metal dissolved in ethylenediamine, the polysaccharides were found to strongly resemble rhamnogalacturonan l. However, unlike rhamnogalacturonan l that characteristically had equal amounts of 2- and 2,4-linked rhamnosyl residues in its backbone, the polysaccharides extracted in Na{sub 2}CO{sub 3} at 1{degree}C had markedly disparate ratios of 2- to 2,4-linked rhamnosyl residues. We concluded that polysaccharides similar to rhamnogalacturonan l but with different degrees of branching are present in the walls of suspension-cultured sycamore cells.
- OSTI ID:
- 6906225
- Journal Information:
- Plant Physiology; (USA), Vol. 89:2; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structure of plant cell walls. VIII. A new pectic polysaccharide
Structure of plant cell walls. X. Rhamnogalacturonan I, a structurally complex pectic polysaccharide in the walls of suspension-cultured sycamore cells