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Protein

Flavone 3'-O-methyltransferase 1

Gene

OMT1

Organism
Arabidopsis thaliana (Mouse-ear cress)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Methylates OH residues of flavonoid compounds. Converts quercetin into isorhamnetin. Dihydroquercetin is not a substrate. Catalyzes the methylation of monolignols, the lignin precursors. Does not contribute to the phenylpropanoid pattern of the pollen tryphine, but is probably confined to isorhamnetin glycoside biosynthesis (PubMed:10700397, PubMed:12777055, PubMed:20652169, PubMed:22258746). Involved in melatonin biosynthesis. Can function as acetylserotonin O-methyltransferase. Catalyzes the transfer of a methyl group onto N-acetylserotonin, producing melatonin (N-acetyl-5-methoxytryptamine) (PubMed:25039887).5 Publications

Catalytic activityi

S-adenosyl-L-methionine + 3'-hydroxyflavone = S-adenosyl-L-homocysteine + 3'-methoxyflavone.1 Publication
S-adenosyl-L-methionine + N-acetylserotonin = S-adenosyl-L-homocysteine + melatonin.1 Publication
S-adenosyl-L-methionine + 3,4-dihydroxy-trans-cinnamate = S-adenosyl-L-homocysteine + 3-methoxy-4-hydroxy-trans-cinnamate.1 Publication

Enzyme regulationi

Does not require magnesium. Completely inhibited by 5 mM of either NiSO4 or p-chloromercuribenzoate (pCMB). Acetylserotonin O-methyltransferase activity is inhibited by caffeate (PubMed:25039887).2 Publications

Kineticsi

  1. KM=1.76 µM for quercetin (at 30 degrees Celsius, PubMed:10700397)2 Publications
  2. KM=3.38 µM for myricetin (at 30 degrees Celsius, PubMed:10700397)2 Publications
  3. KM=24.2 µM for caffeic acid (at pH 7.5, PubMed:20652169)2 Publications
  4. KM=233 µM for N-acetylserotonin (at pH 7.8 and 37 degrees Celsius)1 Publication
  5. KM=32 µM for 5-OH ferulic acid (at pH 7.5, PubMed:20652169)2 Publications
  6. KM=19.7 µM for caffeyl aldehyde (at pH 7.5, PubMed:20652169)2 Publications
  7. KM=17.9 µM for 5-OH coniferyl aldehyde (at pH 7.5, PubMed:20652169)2 Publications
  8. KM=51.5 µM for caffeyl alcohol (at pH 7.5, PubMed:20652169)2 Publications
  9. KM=31.6 µM for 5-OH coniferyl alcohol (at pH 7.5, PubMed:20652169)2 Publications
  10. KM=23.7 µM for quercetin (at pH 7.5, PubMed:20652169)2 Publications
  1. Vmax=384.6 pmol/sec/mg enzyme with quercetin as substrate2 Publications
  2. Vmax=227.3 pmol/sec/mg enzyme with myricetin as substrate2 Publications
  3. Vmax=3.8 pmol/sec/µg enzyme with quercetin as substrate (at pH 7.5, PubMed:20652169)2 Publications
  4. Vmax=51.9 pmol/sec/µg enzyme with 5-OH coniferyl alcohol as substrate (at pH 7.5, PubMed:20652169)2 Publications
  5. Vmax=35.3 pmol/sec/µg enzyme with caffeyl alcohol as substrate (at pH 7.5, PubMed:20652169)2 Publications
  6. Vmax=66.2 pmol/sec/µg enzyme with 5-OH coniferyl aldehyde as substrate (at pH 7.5, PubMed:20652169)2 Publications
  7. Vmax=35.9 pmol/sec/µg enzyme with caffeyl aldehyde as substrate (at pH 7.5, PubMed:20652169)2 Publications
  8. Vmax=30.1 pmol/sec/µg enzyme with 5-OH ferulic acid as substrate (at pH 7.5, PubMed:20652169)2 Publications
  9. Vmax=14.6 pmol/sec/µg enzyme with caffeic acid as substrate (at pH 7.5, PubMed:20652169)2 Publications
  10. Vmax=1800 pmol/min/mg enzyme with N-acetylserotonin as substrate (at pH 7.8 and 37 degrees Celsius)1 Publication

pH dependencei

Optimum pH is 7.5 (PubMed:10700397, PubMed:20652169). Optimum pH is 7.8 for acetylserotonin O-methyltransferase activity (PubMed:25039887).3 Publications

Temperature dependencei

Optimum temperature is 37 degrees Celsius for acetylserotonin O-methyltransferase activity.1 Publication

Pathwayi: quercetin degradation

This protein is involved in the pathway quercetin degradation, which is part of Flavonoid metabolism.
View all proteins of this organism that are known to be involved in the pathway quercetin degradation and in Flavonoid metabolism.

Pathwayi: melatonin biosynthesis

This protein is involved in step 1 of the subpathway that synthesizes melatonin from serotonin.Curated
Proteins known to be involved in the 2 steps of the subpathway in this organism are:
  1. Flavone 3'-O-methyltransferase 1 (OMT1)
  2. no protein annotated in this organism
This subpathway is part of the pathway melatonin biosynthesis, which is itself part of Aromatic compound metabolism.
View all proteins of this organism that are known to be involved in the subpathway that synthesizes melatonin from serotonin, the pathway melatonin biosynthesis and in Aromatic compound metabolism.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei129SubstrateBy similarity1
Binding sitei206S-adenosyl-L-methionine; via carbonyl oxygenBy similarity1
Binding sitei229S-adenosyl-L-methioninePROSITE-ProRule annotation1
Binding sitei249S-adenosyl-L-methionineBy similarity1
Binding sitei250S-adenosyl-L-methionine; via amide nitrogenBy similarity1
Binding sitei263S-adenosyl-L-methionineBy similarity1
Active sitei267Proton acceptorPROSITE-ProRule annotation1
Active sitei2951 Publication1
Active sitei3271 Publication1

GO - Molecular functioni

  • acetylserotonin O-methyltransferase activity Source: UniProtKB-EC
  • caffeate O-methyltransferase activity Source: TAIR
  • luteolin O-methyltransferase activity Source: UniProtKB
  • myricetin 3'-O-methyltransferase activity Source: TAIR
  • quercetin 3-O-methyltransferase activity Source: TAIR

GO - Biological processi

  • flavonol biosynthetic process Source: TAIR
  • lignin biosynthetic process Source: TAIR
  • melatonin biosynthetic process Source: UniProtKB-KW
Complete GO annotation...

Keywords - Molecular functioni

Methyltransferase, Transferase

Keywords - Biological processi

Melatonin biosynthesis

Keywords - Ligandi

S-adenosyl-L-methionine

Enzyme and pathway databases

BRENDAi2.1.1.42. 399.
2.1.1.76. 399.
ReactomeiR-ATH-209931. Serotonin and melatonin biosynthesis.
UniPathwayiUPA00724.
UPA00837; UER00815.

Names & Taxonomyi

Protein namesi
Recommended name:
Flavone 3'-O-methyltransferase 1 (EC:2.1.1.42)
Short name:
AtOMT1
Alternative name(s):
Acetylserotonin O-methyltransferase OMT1Curated (EC:2.1.1.41 Publication)
Caffeate O-methyltransferase 1 (EC:2.1.1.68)
Quercetin 3'-O-methyltransferase 1
Gene namesi
Name:OMT1
Synonyms:COMT1
Ordered Locus Names:At5g54160
ORF Names:K18G13.3
OrganismiArabidopsis thaliana (Mouse-ear cress)
Taxonomic identifieri3702 [NCBI]
Taxonomic lineageiEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaerosidsmalvidsBrassicalesBrassicaceaeCamelineaeArabidopsis
Proteomesi
  • UP000006548 Componenti: Chromosome 5

Organism-specific databases

TAIRiAT5G54160.

Subcellular locationi

GO - Cellular componenti

  • cytoplasm Source: TAIR
  • nucleus Source: TAIR
  • plasma membrane Source: TAIR
  • plasmodesma Source: TAIR
Complete GO annotation...

Pathology & Biotechi

Disruption phenotypei

Reduced levels of syringyl (S) units in lignins that contain more 5-hydroxyguaiacyl units (5-OH-G), the precursors of S-units. Substitution of sinapyl (S) alcohol-derived substructures by 5-hydroxyconiferyl alcohol (5OHG)-derived moieties in fiber cell walls. No effect on hydroxycinnamic acid amides in pollen.3 Publications

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000632171 – 363Flavone 3'-O-methyltransferase 1Add BLAST363

Proteomic databases

PaxDbiQ9FK25.
PRIDEiQ9FK25.

PTM databases

iPTMnetiQ9FK25.

Expressioni

Tissue specificityi

Expressed in seedlings, leaves, stems, flowers and siliques, mostly in vascular tissues. Mostly expressed in the apical part of the stems and in roots. Expressed in the endothecium and the epidermal anther, but not in the tapetum. Also detected in all epidermal tissues of flower organs, including petals, sepals and the tip of the stigma.2 Publications

Developmental stagei

Observed in young seedling and progressively restricted to vascular tissues. Present in whole blade of young leaves but confined to the vascular tissues of mature leaves. In stems, mostly present in xylem, mature phloem and differentiating fibers. In siliques, only present in the lignified extremities. Expressed during early and late stages of flower development.2 Publications

Gene expression databases

GenevisibleiQ9FK25. AT.

Interactioni

Subunit structurei

Monomer.1 Publication

Protein-protein interaction databases

BioGridi20748. 4 interactors.
IntActiQ9FK25. 4 interactors.
MINTiMINT-8066865.
STRINGi3702.AT5G54160.1.

Structurei

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1NIImodel-A1-363[»]
ProteinModelPortaliQ9FK25.
SMRiQ9FK25.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Belongs to the class I-like SAM-binding methyltransferase superfamily. Cation-independent O-methyltransferase family. COMT subfamily.PROSITE-ProRule annotation

Phylogenomic databases

eggNOGiKOG3178. Eukaryota.
ENOG410XS7T. LUCA.
HOGENOMiHOG000238276.
KOiK13066.
OMAiISINARP.
OrthoDBiEOG09360E51.
PhylomeDBiQ9FK25.

Family and domain databases

Gene3Di1.10.10.10. 1 hit.
3.40.50.150. 1 hit.
InterProiIPR016461. O-MeTrfase_COMT.
IPR001077. O_MeTrfase_2.
IPR012967. Plant_MeTrfase_dimerisation.
IPR029063. SAM-dependent_MTases.
IPR011991. WHTH_DNA-bd_dom.
[Graphical view]
PfamiPF08100. Dimerisation. 1 hit.
PF00891. Methyltransf_2. 1 hit.
[Graphical view]
PIRSFiPIRSF005739. O-mtase. 1 hit.
SUPFAMiSSF46785. SSF46785. 1 hit.
SSF53335. SSF53335. 1 hit.
PROSITEiPS51683. SAM_OMT_II. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Q9FK25-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MGSTAETQLT PVQVTDDEAA LFAMQLASAS VLPMALKSAL ELDLLEIMAK
60 70 80 90 100
NGSPMSPTEI ASKLPTKNPE APVMLDRILR LLTSYSVLTC SNRKLSGDGV
110 120 130 140 150
ERIYGLGPVC KYLTKNEDGV SIAALCLMNQ DKVLMESWYH LKDAILDGGI
160 170 180 190 200
PFNKAYGMSA FEYHGTDPRF NKVFNNGMSN HSTITMKKIL ETYKGFEGLT
210 220 230 240 250
SLVDVGGGIG ATLKMIVSKY PNLKGINFDL PHVIEDAPSH PGIEHVGGDM
260 270 280 290 300
FVSVPKGDAI FMKWICHDWS DEHCVKFLKN CYESLPEDGK VILAECILPE
310 320 330 340 350
TPDSSLSTKQ VVHVDCIMLA HNPGGKERTE KEFEALAKAS GFKGIKVVCD
360
AFGVNLIELL KKL
Length:363
Mass (Da):39,618
Last modified:March 1, 2001 - v1
Checksum:iB4380028D89C43DC
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti229D → N in AAB96879 (PubMed:9349713).Curated1
Sequence conflicti295E → V in CAA81580 (PubMed:8580968).Curated1
Sequence conflicti301T → S in CAA81580 (PubMed:8580968).Curated1
Sequence conflicti348V → C in CAA81580 (PubMed:8580968).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U70424 mRNA. Translation: AAB96879.1.
AB013387 Genomic DNA. Translation: BAB11578.1.
CP002688 Genomic DNA. Translation: AED96460.1.
AY062837 mRNA. Translation: AAL32915.1.
AY081565 mRNA. Translation: AAM10127.1.
AY087297 mRNA. Translation: AAM64849.1.
Z27062 mRNA. Translation: CAA81580.1.
RefSeqiNP_200227.1. NM_124796.4.
UniGeneiAt.47593.
At.72792.
At.74847.

Genome annotation databases

EnsemblPlantsiAT5G54160.1; AT5G54160.1; AT5G54160.
GeneIDi835504.
GrameneiAT5G54160.1; AT5G54160.1; AT5G54160.
KEGGiath:AT5G54160.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U70424 mRNA. Translation: AAB96879.1.
AB013387 Genomic DNA. Translation: BAB11578.1.
CP002688 Genomic DNA. Translation: AED96460.1.
AY062837 mRNA. Translation: AAL32915.1.
AY081565 mRNA. Translation: AAM10127.1.
AY087297 mRNA. Translation: AAM64849.1.
Z27062 mRNA. Translation: CAA81580.1.
RefSeqiNP_200227.1. NM_124796.4.
UniGeneiAt.47593.
At.72792.
At.74847.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1NIImodel-A1-363[»]
ProteinModelPortaliQ9FK25.
SMRiQ9FK25.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi20748. 4 interactors.
IntActiQ9FK25. 4 interactors.
MINTiMINT-8066865.
STRINGi3702.AT5G54160.1.

PTM databases

iPTMnetiQ9FK25.

Proteomic databases

PaxDbiQ9FK25.
PRIDEiQ9FK25.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblPlantsiAT5G54160.1; AT5G54160.1; AT5G54160.
GeneIDi835504.
GrameneiAT5G54160.1; AT5G54160.1; AT5G54160.
KEGGiath:AT5G54160.

Organism-specific databases

TAIRiAT5G54160.

Phylogenomic databases

eggNOGiKOG3178. Eukaryota.
ENOG410XS7T. LUCA.
HOGENOMiHOG000238276.
KOiK13066.
OMAiISINARP.
OrthoDBiEOG09360E51.
PhylomeDBiQ9FK25.

Enzyme and pathway databases

UniPathwayiUPA00724.
UPA00837; UER00815.
BRENDAi2.1.1.42. 399.
2.1.1.76. 399.
ReactomeiR-ATH-209931. Serotonin and melatonin biosynthesis.

Miscellaneous databases

PROiQ9FK25.

Gene expression databases

GenevisibleiQ9FK25. AT.

Family and domain databases

Gene3Di1.10.10.10. 1 hit.
3.40.50.150. 1 hit.
InterProiIPR016461. O-MeTrfase_COMT.
IPR001077. O_MeTrfase_2.
IPR012967. Plant_MeTrfase_dimerisation.
IPR029063. SAM-dependent_MTases.
IPR011991. WHTH_DNA-bd_dom.
[Graphical view]
PfamiPF08100. Dimerisation. 1 hit.
PF00891. Methyltransf_2. 1 hit.
[Graphical view]
PIRSFiPIRSF005739. O-mtase. 1 hit.
SUPFAMiSSF46785. SSF46785. 1 hit.
SSF53335. SSF53335. 1 hit.
PROSITEiPS51683. SAM_OMT_II. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiOMT1_ARATH
AccessioniPrimary (citable) accession number: Q9FK25
Secondary accession number(s): O49964, Q42170
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 19, 2002
Last sequence update: March 1, 2001
Last modified: November 30, 2016
This is version 125 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Arabidopsis thaliana
    Arabidopsis thaliana: entries and gene names
  2. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  3. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  4. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.