Caffeoyl-CoA O-methyltransferase that methylates caffeoyl-CoA and 5-hydroxyferuloyl-CoA in phenylpropanoid/lignin metabolism.
The preferred accession for this review is O65922. These relationships are manually assessed.
REFERENCE PROTEOME EQUIVALENT · Reviewed 2026-10-19
Reference proteome: UP000006729
Retain O65922 as the preferred Swiss-Prot accession. A0A2K2C664 represents the same protein sequence at the corresponding reference-proteome locus, supported by exact sequence identity and a shared Gramene identifier. The source cultivars differ; this relationship does not assert that all GO annotations can be transferred automatically.
The current Swiss-Prot and TrEMBL records have identical full-length 247-residue sequences and share UniParc UPI00000ACED6.
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
sequence_identical: true primary_sequence_length: 247 alternative_sequence_length: 247 shared_uniparc_id: UPI00000ACED6
Both current records cross-reference Gramene Potri.001G304800.1.v4.1; the Swiss-Prot record also has this EnsemblPlants identifier, and the reference-proteome entry names locus POPTR_001G304800. This independently supports the counterpart assignment.
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
database: Gramene id: Potri.001G304800.1.v4.1
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
value: POPTR_001G304800
The live UniProt records and proteome metadata place A0A2K2C664, but not O65922, in reference proteome UP000006729 for the same taxon (NCBITaxon:3694).
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
reference_proteome: UP000006729 proteome_is_reference: true proteome_taxon_matches: true primary_in_reference_proteome: false alternative_in_reference_proteome: true
UniSave entry versions 90 (2015), 119 (2020), and 130 (2024) have no Proteomes cross-reference. These samples establish longstanding absence at those dates, not a recent dropout or uninterrupted absence between samples; they do not explain why UniProt omitted the association.
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
sampled_history_versions: - 90 - 119 - 130 sampled_versions_with_proteome_links: []
The Swiss-Prot source material is cultivar Trichobel, whereas the reference proteome represents cultivar Nisqually. This provides context for separate records but does not establish UniProt's reason for keeping the Swiss-Prot accession outside the proteome.
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
RC STRAIN=cv. Trichobel; TISSUE=Xylem;
file:POPTR/CCOAOMT2/CCOAOMT2-record-evidence.yaml
strain: cv. Nisqually
Definition: The chemical reactions and pathways resulting in the formation of polysaccharides modified with feruloyl groups in the plant cell wall.
Justification: The reviewed UniProt entry states that Populus CCoAOMT plays a role in synthesis of feruloylated polysaccharides, but existing GO lignin and broad phenylpropanoid terms do not capture this wall-polysaccharide feruloylation role.
Parent term: phenylpropanoid biosynthetic process
Supporting Evidence:
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0008171 O-methyltransferase activity | IEA GO_REF:0000002 | MODIFY | Summary: O-methyltransferase activity is correct but too broad for a characterized caffeoyl-CoA O-methyltransferase. Reason: Use the specific EC/Rhea-supported caffeoyl-CoA O-methyltransferase term. Proposed replacements: caffeoyl-CoA O-methyltransferase activity Supporting Evidence: file:POPTR/CCOAOMT2/CCOAOMT2-uniprot.txt RecName: Full=Caffeoyl-CoA O-methyltransferase; EC=2.1.1.104. |
| GO:0042409 caffeoyl-CoA O-methyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Caffeoyl-CoA O-methyltransferase activity is the core molecular function. Reason: The UniProt entry and EC assignment match this term directly. Supporting Evidence: file:POPTR/CCOAOMT2/CCOAOMT2-uniprot.txt Reaction=(E)-caffeoyl-CoA + S-adenosyl-L-methionine = (E)-feruloyl-CoA + S-adenosyl-L-homocysteine + H(+). |
| GO:0009699 phenylpropanoid biosynthetic process | IEA GO_REF:0000041 | MODIFY | Summary: Phenylpropanoid biosynthesis is correct but less specific than the experimentally supported lignin-biosynthesis role of Populus CCoAOMT. Reason: The Populus xylem down-regulation study directly links CCoAOMT to lignin amount, while the reviewed entry also supports feruloylated-polysaccharide/cell-wall reinforcement roles. Proposed replacements: lignin biosynthetic process Supporting Evidence: PMID:10934215 To clarify the in vivo role of CCoAOMT in lignin biosynthesis, transgenic poplars with 10% residual CCoAOMT protein levels in the stem xylem were generated. PMID:10934215 the affected transgenic lines had a 12% reduced Klason lignin content file:POPTR/CCOAOMT2/CCOAOMT2-uniprot.txt DR GO; GO:0009809; P:lignin biosynthetic process; IEA:UniProtKB-KW. |
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Download this section (compressed HTML)Q: How much does CCOAOMT2 contribute to lignin composition relative to CCOAOMT1 in xylem?
Q: What fraction of CCOAOMT2 activity supports monolignol biosynthesis versus feruloylated polysaccharide synthesis in Populus xylem?
Experiment: Create isoform-specific knockdowns and measure lignin monomer composition and wall-bound ferulate.
Type: targeted functional assay
CCOAOMT2-uniprot.txt and CCOAOMT2-goa.tsv.Loading supporting content…
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