Journal of Plant Research

, Volume 108, Issue 1, pp 137–148

Endo-xyloglucan transferase, a new class of transferase involved in cell wall construction

  • Kazuhiko Nishitani
Invited Article

DOI: 10.1007/BF02344317

Cite this article as:
Nishitani, K. J. Plant Res. (1995) 108: 137. doi:10.1007/BF02344317

Abstract

Cell shape in plants is constrained by cell walls, which are thick yet dynamic structures composed of crystalline cellulose microfibrils and matrix polymers. Xyloglucans are the principal component of the matrix polymers and bind tightly to the surface of cellulose microfibrils and thereby cross-link them to form an interwoven xyloglucan-cellulose network structure. Thus, cleavage and reconnection of the cross-links between xyloglucan molecules are required for the rearrangement of the cell wall architecture, the process essential for both cell wall expansion and the wall deposition occurring during cell growth and differentiation. Endoxyloglucan transferase (EXT) is a newly identified class of transferase that catalyzes molecular grafting between xyloglucan molecules. This enzyme catalyzes both endo-type splitting of a xyloglucan molecule and reconnection of a newly generated reducing terminus of the xyloglucan to the non-reducing terminus of another xyloglucan molecule, thereby mediating molecular grafting between xyloglucan cross-links in plant cell walls. Molecular cloning and sequencing of EXT-cDNAs derived from five different plant species includingA. thaliana andV. angularis has revealed that the amino acid sequence of the mature protein is extensively conserved in the five different plant species, indicating that EXT protein is ubiquitous among higher plants. This structural study has also disclosed the presence of a group of xyloglucan related proteins (XRPs) with transferase activity in higher plants. Current data strongly suggest that these proteins are involved in a wide spectrum of physiological activities including cell wall expansion and deposition in growing cell walls.

Key words

Cell wall deposition Endo-xyloglucan transferase (EXT) Gene expression Molecular grafting Xyloglucan Xyloglucan related protein (XRP) 

Abbreviations

EXT

endo-xyloglucan transferase

GPC

gel permeation chromatography

XRP

xyloglucan related protein

XET

xyloglucan endotransglycosylase

Copyright information

© The Botanical Society of Japan 1995

Authors and Affiliations

  • Kazuhiko Nishitani
    • 1
  1. 1.College of Liberal ArtsKagoshima UniversityKagoshimaJapan

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