Please use this identifier to cite or link to this item:
Scopus Web of Science® Altmetric
Type: Journal article
Title: A barley xyloglucan xyloglucosyl transferase covalently links xyloglucan, cellulosic substrates, and (1 3;1 4)-β-D-glucans
Other Titles: A barley xyloglucan xyloglucosyl transferase covalently links xyloglucan, cellulosic substrates, and (1 3;1 4)-beta-D-glucans
Author: Hrmova, M.
Farkas, V.
Lahnstein, J.
Fincher, G.
Citation: Journal of Biological Chemistry, 2007; 282(17):12951-12962
Publisher: Amer Soc Biochemistry Molecular Biology Inc
Issue Date: 2007
ISSN: 0021-9258
Statement of
Maria Hrmova, Vladimir Farkas, Jelle Lahnstein, and Geoffrey B. Fincher
Abstract: Molecular interactions between wall polysaccharides, which include cellulose and a range of noncellulosic polysaccharides such as xyloglucans and (1,3;1,4)-β-d-glucans, are fundamental to cell wall properties. These interactions have been assumed to be noncovalent in nature in most cases. Here we show that a highly purified barley xyloglucan xyloglucosyl transferase HvXET5 (EC, a member of the GH16 group of glycoside hydrolases, catalyzes the in vitro formation of covalent linkages between xyloglucans and cellulosic substrates and between xyloglucans and (1,3;1,4)-β-d-glucans. The rate of covalent bond formation catalyzed by HvXET5 with hydroxyethylcellulose (HEC) is comparable with that on tamarind xyloglucan, whereas that with (1,3; 1,4)-β-d-glucan is significant but slower. Matrix-assisted laser desorption ionization time-of-flight mass spectrometric analyses showed that oligosaccharides released from the fluorescent HEC:xyloglucan conjugate by a specific (1,4)-β-dglucan endohydrolase consisted of xyloglucan substrate with one, two, or three glucosyl residues attached. Ancillary peaks contained hydroxyethyl substituents (m/z 45) and confirmed that the parent material consisted of HEC covalently linked with xyloglucan. Similarly, partial hydrolysis of the (1,3;1,4)-β-d-glucan:xyloglucan conjugate by a specific (1,3;1,4)-β-d-glucan endohydrolase revealed the presence of a series of fluorescent oligosaccharides that consisted of the fluorescent xyloglucan acceptor substrate linked covalently with 2-6 glucosyl residues. These findings raise the possibility that xyloglucan endo-transglucosylases could link different polysaccharides in vivo and hence influence cell wall strength, flexibility, and porosity.
Keywords: Cell Wall; Hordeum; Glucans; Cellulose; Glycosyltransferases; Xylans; Plant Proteins; Porosity
Rights: Copyright © 2007 by the American Society for Biochemistry and Molecular Biology
RMID: 0020070625
DOI: 10.1074/jbc.M611487200
Published version:
Appears in Collections:Agriculture, Food and Wine publications

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.