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Protein

Flavone 3'-O-methyltransferase 1

Gene

OMT1

Organism
Arabidopsis thaliana (Mouse-ear cress)
Status
Reviewed-Annotation score: -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)1 Publication
  2. KM=3.38 µM for myricetin (at 30 degrees Celsius)1 Publication
  3. KM=24.2 µM for caffeic acid (at pH 7.5)1 Publication
  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)1 Publication
  6. KM=19.7 µM for caffeyl aldehyde (at pH 7.5)1 Publication
  7. KM=17.9 µM for 5-OH coniferyl aldehyde (at pH 7.5)1 Publication
  8. KM=51.5 µM for caffeyl alcohol (at pH 7.5)1 Publication
  9. KM=31.6 µM for 5-OH coniferyl alcohol (at pH 7.5)1 Publication
  10. KM=23.7 µM for quercetin (at pH 7.5)1 Publication
  1. Vmax=384.6 pmol/sec/mg enzyme with quercetin as substrate1 Publication
  2. Vmax=227.3 pmol/sec/mg enzyme with myricetin as substrate1 Publication
  3. Vmax=3.8 pmol/sec/µg enzyme with quercetin as substrate (at pH 7.5)1 Publication
  4. Vmax=51.9 pmol/sec/µg enzyme with 5-OH coniferyl alcohol as substrate (at pH 7.5)1 Publication
  5. Vmax=35.3 pmol/sec/µg enzyme with caffeyl alcohol as substrate (at pH 7.5)1 Publication
  6. Vmax=66.2 pmol/sec/µg enzyme with 5-OH coniferyl aldehyde as substrate (at pH 7.5)1 Publication
  7. Vmax=35.9 pmol/sec/µg enzyme with caffeyl aldehyde as substrate (at pH 7.5)1 Publication
  8. Vmax=30.1 pmol/sec/µg enzyme with 5-OH ferulic acid as substrate (at pH 7.5)1 Publication
  9. Vmax=14.6 pmol/sec/µg enzyme with caffeic acid as substrate (at pH 7.5)1 Publication
  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. Acetylserotonin O-methyltransferase (ASMT), 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
  • protein dimerization activity Source: InterPro
  • quercetin 3'-O-methyltransferase activity Source: UniProtKB-EC
  • 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-UniPathway

Keywordsi

Molecular functionMethyltransferase, Transferase
Biological processMelatonin biosynthesis
LigandS-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

AraportiAT5G54160
TAIRilocus:2153423 AT5G54160

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cell wall Cytoskeleton Vacuole Chloroplast Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertion Graphics by Christian Stolte; Source: COMPARTMENTS

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

ExpressionAtlasiQ9FK25 baseline and differential
GenevisibleiQ9FK25 AT

Interactioni

Subunit structurei

Monomer.1 Publication

GO - Molecular functioni

Protein-protein interaction databases

BioGridi20748, 4 interactors
IntActiQ9FK25, 4 interactors
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
OMAiVIIAECL
OrthoDBiEOG09360E51
PhylomeDBiQ9FK25

Family and domain databases

Gene3Di1.10.10.10, 1 hit
InterProiView protein in InterPro
IPR016461 O-MeTrfase_COMT
IPR001077 O_MeTrfase_2
IPR012967 Plant_MeTrfase_dimerisation
IPR029063 SAM-dependent_MTases
IPR036388 WH-like_DNA-bd_sf
IPR036390 WH_DNA-bd_sf
PfamiView protein in Pfam
PF08100 Dimerisation, 1 hit
PF00891 Methyltransf_2, 1 hit
PIRSFiPIRSF005739 O-mtase, 1 hit
SUPFAMiSSF46785 SSF46785, 1 hit
SSF53335 SSF53335, 1 hit
PROSITEiView protein in PROSITE
PS51683 SAM_OMT_II, 1 hit

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

Similar proteinsi

Entry informationi

Entry nameiOMT1_ARATH
AccessioniPrimary (citable) accession number: Q9FK25
Secondary accession number(s): O49964, Q42170
Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 19, 2002
Last sequence update: March 1, 2001
Last modified: April 25, 2018
This is version 135 of the entry and version 1 of the sequence. See 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

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