Journal article
Insights into lignin primary structure and deconstruction from Arabidopsis thaliana COMT (caffeic acid O-methyl transferase) mutant Atomt1
Organic & biomolecular chemistry, Vol.8(17), pp.3928-3946
09/07/2010
Handle:
https://hdl.handle.net/2376/118489
PMID: 20652169
Abstract
The Arabidopsis mutant Atomt1 lignin differs from native lignin in wild type plants, in terms of sinapyl (S) alcohol-derived substructures in fiber cell walls being substituted by 5-hydroxyconiferyl alcohol (5OHG)-derived moieties. During programmed lignin assembly, these engender formation of benzodioxane substructures due to intramolecular cyclization of their quinone methides that are transiently formed following 8-O-4' radical-radical coupling. Thioacidolytic cleavage of the 8-O-4' inter-unit linkages in the Atomt1 mutant, relative to the wild type, indicated that cleavable sinapyl (S) and coniferyl (G) alcohol-derived monomeric moieties were stoichiometrically reduced by a circa 2 : 1 ratio. Additionally, lignin degradative analysis resulted in release of a 5OHG-5OHG-G trimer from the Atomt1 mutant, which then underwent further cleavage. Significantly, the trimeric moiety released provides new insight into lignin primary structure: during polymer assembly, the first 5OHG moiety is linked via a C8-O-X inter-unit linkage, whereas subsequent addition of monomers apparently involves sequential addition of 5OHG and G moieties to the growing chain in a 2 : 1 overall stoichiometry. This quantification data thus provides further insight into how inter-unit linkage frequencies in native lignins are apparently conserved (or near conserved) during assembly in both instances, as well as providing additional impetus to resolve how the overall question of lignin macromolecular assembly is controlled in terms of both type of monomer addition and primary sequence.
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Details
- Title
- Insights into lignin primary structure and deconstruction from Arabidopsis thaliana COMT (caffeic acid O-methyl transferase) mutant Atomt1
- Creators
- Syed G A Moinuddin - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USAMichaël JourdesDhrubojyoti D LaskarChanyoung KiClaudia L CardenasKye-Won KimDianzhong ZhangLaurence B DavinNorman G Lewis
- Publication Details
- Organic & biomolecular chemistry, Vol.8(17), pp.3928-3946
- Academic Unit
- Biological Chemistry, Institute of
- Publisher
- England
- Identifiers
- 99900548573301842
- Language
- English
- Resource Type
- Journal article