Structural Basis for the Modulation of Lignin Monomer Methylation by Caffeic Acid/5-Hydroxyferulic Acid 3/5-O-Methyltransferase
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چکیده
منابع مشابه
Structural basis for the modulation of lignin monomer methylation by caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase.
Caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase (COMT) from alfalfa is an S-adenosyl-L-Met-dependent O-methyltransferase involved in lignin biosynthesis. COMT methylates caffeoyl- and 5-hydroxyferuloyl-containing acids, aldehydes, and alcohols in vitro while displaying a kinetic preference for the alcohols and aldehydes over the free acids. The 2.2-A crystal structure of COMT in comp...
متن کاملNucleotide sequence of a Populus tremuloides gene encoding bispecific caffeic acid/5-hydroxyferulic acid O-methyltransferase.
Bi-specific OMT (EC 2.1.1.68) catalyzes the meta-specific methylation of caffeic acid and 5-hydroxyferulic acid to ferulic acid and sinapic acid, respectively (Higuchi, 1990). It is one of the key enzymes in angiosperm dicots mediating the formation of unique precursors for syringyl lignin, which is generally absent in gymnosperms (Higuchi, 1990). OMT has been purified and its cDNA clones isola...
متن کاملProbing the mysteries of lignin biosynthesis: the crystal structure of caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase provides new insights.
Caffeic acid/5-hydroxyferulic acid 3/5O -methyltransferase (COMT) is a small-molecule S -adenosylL -Met–dependent O -methyltransferase (OMT) that is one of the principal enzymes in the complex network of reactions that take place as part of lignin biosynthesis (Figure 1). Plants contain a wide variety of S -adenosylL -Met–dependent OMTs that act on Phe-derived substrates during the production o...
متن کاملCharacterization of a caffeic acid 3-O-methyltransferase from wheat and its function in lignin biosynthesis.
Caffeic acid 3-O-methyltransferase (COMT) catalyzes the multi-step methylation reactions of hydroxylated monomeric lignin precursors, and is believed to occupy a pivotal position in the lignin biosynthetic pathway. A cDNA (TaCM) was identified from wheat and it was found to be expressed constitutively in stem, leaf and root tissues. The deduced amino acid sequence of TaCM showed a high degree o...
متن کاملStructural and compositional modifications in lignin of transgenic alfalfa down-regulated in caffeic acid 3-O-methyltransferase and caffeoyl coenzyme A 3-O-methyltransferase.
Isolated lignins from alfalfa deficient in caffeic acid 3-O-methyltransferase contained benzodioxanes resulting from the incorporation of the novel monomer, 5-hydroxyconiferyl alcohol. Due to the high level incorporated into the soluble lignin fraction and the use of sensitive NMR instrumentation, unique structural features were revealed. A new type of end-unit, the 5-hydroxyguaiacyl glycerol u...
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ژورنال
عنوان ژورنال: The Plant Cell
سال: 2002
ISSN: 1040-4651,1532-298X
DOI: 10.1105/tpc.001412