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Q38J50 (FOMT2_WHEAT) Reviewed, UniProtKB/Swiss-Prot

Last modified May 1, 2013. Version 41. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (1) | Third-party data text xml rdf/xml gff fasta
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Names and origin

Protein namesRecommended name:
Tricetin 3',4',5'-O-trimethyltransferase
Short name=TaOMT2
EC=2.1.1.169
Alternative name(s):
Caffeic acid 3-O-methyltransferase
Short name=TaCM
Flavone O-methyltransferase 2
Gene names
Name:OMT2
OrganismTriticum aestivum (Wheat)
Taxonomic identifier4565 [NCBI]
Taxonomic lineageEukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › Liliopsida › Poales › Poaceae › BEP clade › Pooideae › Triticeae › Triticum

Protein attributes

Sequence length356 AA.
Sequence statusComplete.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Flavonoid B-ring-specific O-methyltransferase with a preference for flavones > dihydroflavones > flavonols that possess at least two B-ring hydroxyl groups. Active with tricetin, 5-hydroxyferulic acid, luteolin, quercitin, eriodictyol, quercetagetin, taxifolin, gossypetin and myricetin. No activity with naringenin, apigenin, kaempferol, 7,8-dihydroxy- or 5,7,8-trihydroxy flavones, chlorogenic acid, gallic acid or daphnetin. Catalyzes the sequential O-methylation of tricetin via 3'-O-methyltricetin, 3',5'-O-methyltricetin to 3',4',5'-O-trimethyltricetin. May also be involved in S lignin biosynthesis. Ref.1 Ref.2

Catalytic activity

3 S-adenosyl-L-methionine + tricetin = 3 S-adenosyl-L-homocysteine + 3',4',5'-O-trimethyltricetin. Ref.1 Ref.2 Ref.3

Subunit structure

Homodimer. The monomer is fully active and dimerization is not required for sequential methylation. Ref.3

Tissue specificity

Expressed in roots, stems and leaves. Ref.2

Miscellaneous

OMT1 has a very low activity with phenylpropanoids (5-hydroxyferulic acid and caffeic acid) while OMT2 has a good activity with them.

Sequence similarities

Belongs to the methyltransferase superfamily. Type 2 family. COMT subfamily.

Biophysicochemical properties

Kinetic parameters:

KM=3.73 µM for tricetin Ref.1 Ref.2

KM=3.33 µM for S-adenosyl-L-methionine

KM=8.36 µM for 5-hydroxyferulic acid

KM=6.59 µM for myricetin

KM=68.75 µM for caffeic acid

KM=83.04 µM for caffeoyl-CoA

KM=95.17 µM for 5-hydroxyferuloyl-CoA

KM=43.72 µM for caffeoyl aldehyde

KM=17.31 µM for 5-hydroxyconiferaldehyde

KM=84.03 µM for caffeoyl alcohol

KM=100.21 µM for 5-hydroxyconiferyl alcohol

Vmax=142.86 pmol/sec/mg enzyme with tricetin as methyl acceptor

Vmax=88.5 pmol/sec/mg enzyme with 5-hydroxyferulic acid as methyl acceptor

Vmax=45.66 pmol/sec/mg enzyme with myricetin as methyl acceptor

Vmax=2.38 nmol/sec/mg enzyme with caffeic acid as methyl acceptor

Vmax=1.26 nmol/sec/mg enzyme with caffeoyl-CoA as methyl acceptor

Vmax=1.28 nmol/sec/mg enzyme with 5-hydroxyferuloyl-CoA as methyl acceptor

Vmax=2.56 nmol/sec/mg enzyme with caffeoyl aldehyde as methyl acceptor

Vmax=1.56 nmol/sec/mg enzyme with 5-hydroxyconiferaldehyde as methyl acceptor

Vmax=3.55 nmol/sec/mg enzyme with caffeoyl alcohol as methyl acceptor

Vmax=2.67 nmol/sec/mg enzyme with 5-hydroxyconiferyl alcohol as methyl acceptor

Ontologies

Keywords
   Biological processFlavonoid biosynthesis
Lignin biosynthesis
   LigandS-adenosyl-L-methionine
   Molecular functionMethyltransferase
Transferase
Gene Ontology (GO)
   Biological_processflavonoid biosynthetic process

Inferred from electronic annotation. Source: UniProtKB-KW

lignin biosynthetic process

Inferred from electronic annotation. Source: UniProtKB-KW

   Molecular_functionO-methyltransferase activity

Inferred from electronic annotation. Source: InterPro

Complete GO annotation...

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 356356Tricetin 3',4',5'-O-trimethyltransferase
PRO_0000403987

Regions

Region123 – 1297Substrate binding By similarity
Region155 – 17319Substrate binding By similarity

Sites

Active site2621Proton acceptor By similarity
Binding site2011S-adenosyl-L-methionine; via carbonyl oxygen By similarity
Binding site2241S-adenosyl-L-methionine By similarity
Binding site2441S-adenosyl-L-methionine By similarity
Binding site2451S-adenosyl-L-methionine; via amide nitrogen By similarity
Binding site2581S-adenosyl-L-methionine By similarity

Experimental info

Sequence conflict891D → E in ABP63535. Ref.2
Sequence conflict2521G → A in ABP63535. Ref.2

Sequences

Sequence LengthMass (Da)Tools
Q38J50 [UniParc].

Last modified November 22, 2005. Version 1.
Checksum: 5EA3037A554E13FB

FASTA35638,570
        10         20         30         40         50         60 
MGSIAAGADE DACMYALQLV SSSILPMTLK NAIELGLLET LMAAGGKFLT PAEVAAKLPS 

        70         80         90        100        110        120 
AANPEAPDMV DRMLRLLASY NVVSCRTEDG KDGRLSRRYG AAPVCKYLTP NEDGVSMSAL 

       130        140        150        160        170        180 
ALMNQDKVLM ESWYYLKDAV LDGGIPFNKA YGMSAFEYHG TDPRFNRVFN EGMKNHSIII 

       190        200        210        220        230        240 
TKKLLESYKG FEGLGTLVDV GGGVGATVAA ITAHYPTIKG INFDLPHVIS EAPPFPGVTH 

       250        260        270        280        290        300 
VGGDMFQKVP SGDAILMKWI LHDWSDEHCA TLLKNCYDAL PAHGKVVLVE CILPVNPEAT 

       310        320        330        340        350 
PKAQGVFHVD MIMLAHNPGG RERYEREFEA LAKGAGFAAM KTTYIYANAW AIEFTK

« Hide

References

[1]"Sequential O-methylation of tricetin by a single gene product in wheat."
Zhou J.M., Gold N.D., Martin V.J., Wollenweber E., Ibrahim R.K.
Biochim. Biophys. Acta 1760:1115-1124(2006) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES.
Strain: cv. Norstar.
[2]"Characterization of a caffeic acid 3-O-methyltransferase from wheat and its function in lignin biosynthesis."
Ma Q.H., Xu Y.
Biochimie 90:515-524(2008) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY, FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES.
Strain: cv. H4564.
[3]"Structure-activity relationships of wheat flavone O-methyltransferase: a homodimer of convenience."
Kornblatt J.A., Zhou J.M., Ibrahim R.K.
FEBS J. 275:2255-2266(2008) [PubMed] [Europe PMC] [Abstract]
Cited for: CATALYTIC ACTIVITY, SUBUNIT.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ		DQ223971 mRNA. Translation: ABB03907.1.
EF413031 mRNA. Translation: ABP63535.1.
UniGeneTa.70123.

3D structure databases

ProteinModelPortalQ38J50.
SMRQ38J50. Positions 8-356.
ModBaseSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Organism-specific databases

GrameneQ38J50.

Enzyme and pathway databases

BioCycMetaCyc:MONOMER-15895.

Family and domain databases

Gene3D1.10.10.10. 1 hit.
InterProIPR016461. COMT.
IPR001077. O_MeTrfase_2.
IPR012967. Plant_MeTrfase_dimerisation.
IPR011991. WHTH_DNA-bd_dom.
[Graphical view]
PfamPF08100. Dimerisation. 1 hit.
PF00891. Methyltransf_2. 1 hit.
[Graphical view]
PIRSFPIRSF005739. O-mtase. 1 hit.
ProtoNetSearch...

Entry information

Entry nameFOMT2_WHEAT
AccessionPrimary (citable) accession number: Q38J50
Secondary accession number(s): B8LGB9
Entry history
Integrated into UniProtKB/Swiss-Prot: February 8, 2011
Last sequence update: November 22, 2005
Last modified: May 1, 2013
This is version 41 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

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