Xyloglucan Fucosyltransferase, an Enzyme Involved in Plant Cell Wall Biosynthesis

Abstract

Cell walls are crucial for development, signal transduction, and disease resistance in plants. Cell walls are made of cellulose, hemicelluloses, and pectins. Xyloglucan (XG), the principal load-bearing hemicellulose of dicotyledonous plants, has a terminal fucosyl residue. A 60-kilodalton fucosyltransferase (FTase) that adds this residue was purified from pea epicotyls. Peptide sequence information from the pea FTase allowed the cloning of a homologous gene, AtFT1, from Arabidopsis. Antibodies raised against recombinant AtFTase immunoprecipitate FTase enzyme activity from solubilized Arabidopsis membrane proteins, and AtFT1 expressed in mammalian COS cells results in the presence of XG FTase activity in these cells.

The Import of S-Adenosylmethionine into the Golgi Apparatus Is Required for the Methylation of Homogalacturonan

“…1B). XG-FT is a type II membrane protein with a catalytic site that faces the lumen of the Golgi apparatus (Perrin et al, 1999;Wulff et al, 2000). Since HGA-MT and XG-FT were measured in the presence of acceptors that cannot cross the membrane, the increases we detected in their activity following the permeabilization of the Golgi vesicle membranes could be explained by the luminal localization of the active site of both enzymes.…”

Quantitative Trait Loci and Comparative Genomics of Cereal Cell Wall Composition

“…Biochemical approaches to identification of the enzymes and genes involved have been hindered by the lability of the enzymes and our ignorance of their biosynthetic mechanisms. Although substantial progress has recently been made on the identification and function of cellulose synthases and the corresponding genes (called CESA) and on several nonprocessive glycosyl transferases such as xylosyl, galactosyl, and fucosyl transferases, little is known about the genes and enzymes involved in synthesis of the backbones of the hemicellulosic polymers (Arioli et al, 1998;Edwards et al, 1999;Perrin et al, 1999;Fagard et al, 2000;Taylor et al, 2000;Faik et al, 2002;Peng et al, 2002;Vanzin et al, 2002).…”

Solubilization of an Arabinan Arabinosyltransferase Activity from Mung Bean Hypocotyls

“…The composition and size of these side chains varies depending on the plant species, tissue type, and stage of development (O'Neill et al, 1990;Carpita and Gibeaut, 1993). In general, the arabinan side chains consist of a linear chain of (135)-linked ␣-l-arabinofuranosyl residues that may be substituted at the O-3 and/or O-2 with additional arabinofuranosyl residues (Carpita and Gibeaut, 1993;Schols and Voragen, 2002).The study of the biosynthesis of plant cell wall polysaccharides in plants is a growing field, but to date, very few genes encoding glycosyltransferases have been characterized (Edwards et al, 1999;Perrin et al, 1999;Faik et al, 2002). Notably, many different transferases must be involved in pectin biosynthesis, but until very recently, none had been isolated or cloned, most likely due to the structural complexity of pectic polysaccharides.…”

“…The study of the biosynthesis of plant cell wall polysaccharides in plants is a growing field, but to date, very few genes encoding glycosyltransferases have been characterized (Edwards et al, 1999;Perrin et al, 1999;Faik et al, 2002). Notably, many different transferases must be involved in pectin biosynthesis, but until very recently, none had been isolated or cloned, most likely due to the structural complexity of pectic polysaccharides.…”