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Visualizing Lignification Dynamics in Plants with Click Chemistry: Dual Labeling is BLISS!
Published on: January 26, 2018
Radical coupling reactions in lignin synthesis: a density functional theory study
Amandeep K Sangha1, Jerry M Parks, Robert F Standaert
1UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831-6309, United States.
The Journal of Physical Chemistry. B
|April 6, 2012
Summary
This study reveals that p-coumaryl alcohol radicals favor self- and cross-coupling reactions, forming lignin dimers. The 8-O-4, 8-8, and 8-5 linkages are the most stable, influencing plant cell wall structure.
Area of Science:
- Plant Biology
- Biochemistry
- Computational Chemistry
Background:
- Lignin is a vital plant cell wall polymer providing structural integrity and defense.
- Lignin biosynthesis involves radical coupling of monolignols like p-coumaryl, coniferyl, and sinapyl alcohols.
Purpose of the Study:
- To computationally investigate the radical-radical coupling reactions in monolignol dimerization.
- To determine the relative stability of different lignin dimer linkages.
Main Methods:
- Density functional theory (DFT) was employed to model monolignol radical dimerization.
- Reaction enthalpies were calculated for various self- and cross-coupling reactions.
Main Results:
- The 8-O-4, 8-8, and 8-5 coupling linkages were found to be the most energetically favorable.
- p-Coumaryl alcohol radicals exhibited the most favorable self- and cross-coupling reactions.
- In cross-coupling, the more reactive radical preferentially couples at its highest spin density site.
Conclusions:
- DFT calculations provide insights into the initial steps of lignin formation.
- The preferential formation of certain linkages, particularly involving p-coumaryl alcohol, shapes lignin structure and properties.
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