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Title: The mechanism of synthesis of a mixed-linkage (1{r{underscore}arrow}3), (1{r{underscore}arrow}4) {beta}-D-glucan in maize. Evidence for multiple sites of glucosyl transfer in the synthase complex

Abstract

The authors examined the mechanism of synthesis in vitro of (1{r{underscore}arrow}3), (1{r{underscore}arrow}4){Beta}-D-glucan ({Beta}-glucan), a growth-specific cell wall polysaccharide round in grasses and cereals. {beta}-Glucan is composed primarily of cellotriosyl and cellotetraosyl units linked by single (1{r{underscore}arrow}3){beta}-linkages. The ratio of cellotriosyl and cellotetraosyl units in the native polymer is strictly controlled at between 2 and 3 in all grasses, whereas the ratios of these units in {Beta}-glucan formed in vitro vary from 1.5 with 5 {micro}M UDP-glucose (GLc) to over 11 with 30 nM substrate. These results support a model in which three sites of glycosyl transfer occur within the synthase complex to produce the cellobiosyl-(1{r{underscore}arrow}3)-D-glucosyl units. The authors propose that failure to fill one of the sites results in the iterative addition of one or more cellobiosyl units to produce the longer cellodextrin units in the polymer. Variations in the UDP-Glc concentration in excised maize (Zea mays) coleoptiles did not result in wide variations in the ratios of cellotriosyl and cellotetraosyl units in {beta}-glucan synthesized in vivo, indicating that other factors control delivery of UDP-Glc to the synthase. In maize sucrose synthase is enriched in Golgi membranes and plasma membranes and may be involved in the control of substrate deliverymore » to {beta}-glucan synthase and cellulose synthase.« less

Authors:
; ;
Publication Date:
Research Org.:
Inst. de Botanica, Sao Paulo (BR)
OSTI Identifier:
20006196
Resource Type:
Journal Article
Journal Name:
Plant Physiology (Bethesda)
Additional Journal Information:
Journal Volume: 120; Journal Issue: 4; Other Information: PBD: Aug 1999; Journal ID: ISSN 0032-0889
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; BIOSYNTHESIS; POLYSACCHARIDES; MAIZE; CELL WALL; CELL MEMBRANES; TRANSFERASES; BIOLOGICAL ACCUMULATION; MEMBRANE TRANSPORT

Citation Formats

Buckeridge, M S, Vergara, C E, and Carpita, N C. The mechanism of synthesis of a mixed-linkage (1{r{underscore}arrow}3), (1{r{underscore}arrow}4) {beta}-D-glucan in maize. Evidence for multiple sites of glucosyl transfer in the synthase complex. United States: N. p., 1999. Web. doi:10.1104/pp.120.4.1105.
Buckeridge, M S, Vergara, C E, & Carpita, N C. The mechanism of synthesis of a mixed-linkage (1{r{underscore}arrow}3), (1{r{underscore}arrow}4) {beta}-D-glucan in maize. Evidence for multiple sites of glucosyl transfer in the synthase complex. United States. https://doi.org/10.1104/pp.120.4.1105
Buckeridge, M S, Vergara, C E, and Carpita, N C. Sun . "The mechanism of synthesis of a mixed-linkage (1{r{underscore}arrow}3), (1{r{underscore}arrow}4) {beta}-D-glucan in maize. Evidence for multiple sites of glucosyl transfer in the synthase complex". United States. https://doi.org/10.1104/pp.120.4.1105.
@article{osti_20006196,
title = {The mechanism of synthesis of a mixed-linkage (1{r{underscore}arrow}3), (1{r{underscore}arrow}4) {beta}-D-glucan in maize. Evidence for multiple sites of glucosyl transfer in the synthase complex},
author = {Buckeridge, M S and Vergara, C E and Carpita, N C},
abstractNote = {The authors examined the mechanism of synthesis in vitro of (1{r{underscore}arrow}3), (1{r{underscore}arrow}4){Beta}-D-glucan ({Beta}-glucan), a growth-specific cell wall polysaccharide round in grasses and cereals. {beta}-Glucan is composed primarily of cellotriosyl and cellotetraosyl units linked by single (1{r{underscore}arrow}3){beta}-linkages. The ratio of cellotriosyl and cellotetraosyl units in the native polymer is strictly controlled at between 2 and 3 in all grasses, whereas the ratios of these units in {Beta}-glucan formed in vitro vary from 1.5 with 5 {micro}M UDP-glucose (GLc) to over 11 with 30 nM substrate. These results support a model in which three sites of glycosyl transfer occur within the synthase complex to produce the cellobiosyl-(1{r{underscore}arrow}3)-D-glucosyl units. The authors propose that failure to fill one of the sites results in the iterative addition of one or more cellobiosyl units to produce the longer cellodextrin units in the polymer. Variations in the UDP-Glc concentration in excised maize (Zea mays) coleoptiles did not result in wide variations in the ratios of cellotriosyl and cellotetraosyl units in {beta}-glucan synthesized in vivo, indicating that other factors control delivery of UDP-Glc to the synthase. In maize sucrose synthase is enriched in Golgi membranes and plasma membranes and may be involved in the control of substrate delivery to {beta}-glucan synthase and cellulose synthase.},
doi = {10.1104/pp.120.4.1105},
url = {https://www.osti.gov/biblio/20006196}, journal = {Plant Physiology (Bethesda)},
issn = {0032-0889},
number = 4,
volume = 120,
place = {United States},
year = {1999},
month = {8}
}