The natural glue that makes plant cells rigid

New research solves an age-old mystery of how sugar molecules in cells join together to form strong substances that cannot be easily broken down.

[Translation by Dr. Nachmani Moshe]

Molecules whose thickness is ten thousand times smaller than the thickness of a human hair can be important in the field of building wooden skyscrapers and in energy saving in paper production processes. New research solves an age-old mystery of how sugar molecules in cells join together to form strong substances that cannot be easily broken down.

The research findings were published in the scientific journal Nature Communications..

The two largest molecules, or polymers, most common in our world are cellulose and xylan, and both are found in the cell walls of materials such as trees and grass. These compounds determine the strength of the materials and their ability to decompose. Researchers have known for a long time that these two polymers must join together in order to create strong cell walls, but the way in which this happens has remained unknown until now: xylan is a long polymer to which several sugar molecules are attached and cellulose is a wide stick-shaped molecule - so how do these two structures connecting together?

"We knew that the answer had to be elegant and simple," explains Professor Paul Dupree from the Department of Biochemistry at the University of Cambridge, who led the research. "And in fact, that's exactly what we found. We discovered that the cellulose molecule causes the xylan molecule to align and thus allows it to connect to the cellulose molecule. This mechanism functions as a kind of glue capable of protecting the cellular molecules or connecting them together, resulting in the creation of particularly strong and stable structures." The findings were revealed following an unexpected discovery observed several years ago in Arabidopsis, a small flowering plant that belongs to the cabbage and mustard families. The researchers discovered that the modifiers on top of the xylan molecule can only be found on one side of it. This finding led the researchers to scan other plants located in the botanical garden of the University of Cambridge and to discover that the phenomenon occurs in all the plants tested, that is, the mechanism developed in an ancient era and it must be important.

For a more thorough study, the researchers used a solid-state NMR method capable of revealing the details of the structure of the material at the nanometer level. With this method, the researchers were able to reveal for the first time ever the nanometer structure in which the cellulose molecule connects to the xylan molecule, thus making the cell walls a strong varnish." Understanding the combined structure of the two molecules can be of great importance in diverse industrial fields such as the production and development of biofuels, paper and agriculture, according to the chief researcher. "One of the biggest barriers to decomposing plants - whether they are intended to be used as biofuels or as food for livestock - has so far been the breakdown of cell walls," explains the researcher. "For example, in the field of paper production - huge amounts of energy are required for this decomposition process. A better understanding of the interrelationship between cellulose and xylan could help to significantly reduce these amounts of energy and lead to significant cost savings." In addition, the new findings could be used in the development of stronger materials - there are already plans to build wooden houses in the UK from particularly sustainable and stable materials, and these findings could help advance this field.

The article describing the study

The news about the study