Protein Complex Within Plant Cell Wall Associated with Secondary Cell-Wall Synthesis

The Science

The plant cell wall polysaccharide pectin is often associated with the tissue softening that occurs during fruit ripening. However, this complex compound is also involved in secondary cell-wall synthesis in grasses and woody plants, helping to give the plant rigidity, but also impeding the deconstruction of plant biomass and hence its conversion into biofuels. Researchers at the DOE BioEnergy Research Center (BESC) have discovered that the pectin-synthesizing enzyme GAUT1 forms an unusual, two-protein complex with a similar protein (GAUT7) that constitutes a critical part of a pectin-synthesizing protein complex. They also showed that this complex plays a role in secondary cell-wall synthesis. Manipulating the formation of this complex may provide a way to modify secondary cell walls, which could either increase available biomass or improve its digestibility for biofuel production.

The Impact

The processing of GAUT1 to remove its N-terminal transmembrane domain and its anchoring in the Golgi by association with GAUT7 provides an example of how specific catalytic domains of plant cell wall biosynthetic glycosyltransferases could be assembled into protein complexes to enable the synthesis of the complex and developmentally and environmentally plastic plant cell wall.

BER Program Manager

Kari Perez

U.S. Department of Energy, Biological and Environmental Research (SC-33)
Biological Systems Science Division
[email protected]

References

Atmodjo, M. A., Y. Sakuragi, X. Zhu, A. J. Burrell, S. S. Mohanty, J. A. Atwood III, R. Orlando, H. V. Scheller, and D. Mohnen. 2011. “Galacturonosyltransferase (GAUT)1 and GAUT7 Are the Core of a Plant Cell Wall Pectin Biosynthetic Homogalacturonan: Galacturonosyltransferase Complex,” Proceedings of the National Academy of Sciences of the United States of America 108(50), 20225-230. DOI:10.1073/pnas.11128116108.