Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniPathway vocabulary mapping
Combined Automated Annotation using Multiple IEA Methods
Plant O-methyltransferases: molecular analysis, common signature and classification.
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Classifies plant O-methyltransferases into families based on sequence conservation and substrate specificity. Identifies five conserved regions as signatures, with regions I and IV involved in SAM and metal binding respectively.
"Five highly conserved regions are proposed as a signature for plant O-methyltransferases, two of which (regions I and IV) are believed to be involved in S-adenosyl-L-methionine and metal binding, respectively."
Developmental expression and substrate specificities of alfalfa caffeic acid 3-O-methyltransferase and caffeoyl coenzyme A 3-O-methyltransferase in relation to lignification.
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Alfalfa CCoAOMT catalyzes O-methylation of caffeoyl and 5-hydroxyferuloyl CoA, with preference for caffeoyl CoA. Expression in vascular tissue precedes lignin deposition.
"Alfalfa CCOMT expressed in Escherichia coli catalyzes O-methylation of caffeoyl and 5-hydroxyferuloyl CoA, with preference for caffeoyl CoA. It has low activity against the free acids."
A novel Mg(2+)-dependent O-methyltransferase in the phenylpropanoid metabolism of Mesembryanthemum crystallinum.
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Characterized CCoAOMT-like enzymes from ice plant, chickweed, Arabidopsis, and tobacco. The Arabidopsis Class II member showed broader substrate specificity including flavonols and caffeoylglucose, forming a novel subclass with functions potentially divergent from lignin biosynthesis.
"the enzymes from the Centrospermae, along with the predicted gene product from A. thaliana, form a novel subclass within the caffeoyl coenzyme A-dependent O-methyltransferases, with potential divergent functions not restricted to lignin monomer biosynthesis"
Tapetum-specific location of a cation-dependent O-methyltransferase in Arabidopsis thaliana.
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At1g67990 (AtTSM1), the tandem duplicate of At1g67980, is tapetum-specific and functions in spermidine hydroxycinnamic acid conjugate biosynthesis. This demonstrates that CCoAOMT family members have divergent, tissue-specific functions beyond lignin.
"The gene At1g67990 is specifically expressed in flower buds, and is not detected in any other organ, such as roots, leaves or stems...the corresponding CCoAOMT-like protein, termed AtTSM1, is located exclusively in the tapetum of developing stamen"
Scopoletin is biosynthesized via ortho-hydroxylation of feruloyl CoA by a 2-oxoglutarate-dependent dioxygenase in Arabidopsis thaliana.
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CCoAOMT1 (At4g34050) is required for scopoletin biosynthesis. T-DNA insertion mutants showed reduced scopoletin/scopolin levels. This establishes At4g34050 as the principal functional CCoAOMT in Arabidopsis, distinct from At1g67980.
"T-DNA insertion mutants of caffeoyl CoA O-methyltransferase 1 (CCoAOMT1) showed significant reduction in scopoletin and scopolin levels in the roots"
Isolation and functional characterization of two Caffeoyl Coenzyme A 3-O-methyltransferases from the fern species Polypodiodes amoena.
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Fern CCoAOMTs localize to cytoplasm and can methylate caffeoyl CoA along with flavones and flavonols. Overexpression in Arabidopsis boosted lignin content.
"The transient expression of a PaCCoAOMT-GFP fusion gene in tobacco demonstrated that in planta, PaCCoAOMTs are likely directed to the cytoplasm"
Falcon (Edison Scientific) deep research report for At1g67980 (Q9C9W3)
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"within the retrieved corpus, there is **no direct biochemical characterization** (purified enzyme assay, kinetic parameters, definitive substrate specificity, metal dependence) and **no direct subcellular localization experiment** specifically for **AT1G67980/Q9C9W3**."
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"A 2024 Arabidopsis lignification-focused thesis compilation explicitly includes **AT1G67980 as CCoAOMT6** in the **phenylpropanoid/monolignol biosynthesis** section, supporting continued use of this locus in modern lignification pathway models"
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"In Arabidopsis roots treated with cellooligomers, **AT1G67980 (CCOAOMT)** was upregulated **3.67-fold** with **p = 6.47 × 10−5**; the study interprets the induced program as involving **cell wall reinforcement** and **defense-related secondary metabolite synthesis** requiring the receptor kinase CORK1"
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"CCoAOMT-family enzymes catalyze **O-methylation reactions** in **monolignol synthesis** affecting lignification and lignin composition; CCoAOMT-like enzymes can be more **substrate-promiscuous**, acting on compounds such as flavonoids, anthocyanins, phenylpropanoids, or alkaloids"
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"In Arabidopsis flower-bud methyltransferase profiling, only COMT1, CCoAOMT1, and AtTSM1 were directly detected; AT1G67980 was **not** detected, likely because its transcript abundance in flowers was far lower (**~100-fold lower**) than abundant OMTs"
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"No retrieved source in this run provides direct experimental evidence (e.g., GFP fusion, fractionation) for AT1G67980 subcellular localization (kuo2024dissectingtheroles pages 30-32, tseng2022cork1alrrmalectin pages 17-18). Any cellular-location statement would be speculative; consequently, localization remains **undetermined from the current evidence set**."
AI review research notes for At1g67980