Reduced number of homogalacturonan domains in pectins of an Arabidopsis mutant enhances the flexibility of the polymer
2008
Ralet, Marie-Christine | Crepeau, Marie-Jeanne | Lefebvre, Jacques | Mouille, Gregory, G. | Höfte, Herman | Thibault, Jean-François | Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA) ; Institut National de la Recherche Agronomique (INRA) | Laboratoire de biologie cellulaire et moléculaire ; Institut National de la Recherche Agronomique (INRA)
International audience
显示更多 [+] 显示较少 [-]英语. Pectins are a family of highly complex multifunctional cell wall polysaccharides. Little is known on the relation between pectin structure, hydrodynamic properties, and cellular function. In this study, we took advantage of the Arabidopsis pectin mutant quasimodo2 (qua2), which specifically lacks half of its homogalacturonan blocks, to study the relationship between the amount of homogalacturonan blocks and the hydrodynamic properties of pectins. It was first shown that, in qua2 pectins, homogalacturonans had maintained the same size as those in the wild type. The persistence lengths of isolated homogalacturonan and rhamnogalacturonan-I blocks were then measured and it was shown that homogalacturonan was over 4-fold more rigid than rhamnogalacturonan-I. WT and qua2 pectins were next compared and it appeared that the specific reduction of the number of homogalacturonan blocks leads to an increased flexibility of qua2 pectins. These results show for the first time how mutant pectins can be used to demonstrate the opposite influence of rhamnogalacturonan-I and homogalacturonan blocks on the hydrodynamic properties of pectins.
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