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Q29U70 (I4OMT_MEDTR) Reviewed, UniProtKB/Swiss-Prot

Last modified January 25, 2012. Version 31. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
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Names and origin

Protein namesRecommended name:
Isoflavone 4'-O-methyltransferase
Short name=MtHI4'OMT
EC=2.1.1.46
Alternative name(s):
2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase
EC=2.1.1.212
Gene names
Name:HI4'OMT
OrganismMedicago truncatula (Barrel medic) (Medicago tribuloides)
Taxonomic identifier3880 [NCBI]
Taxonomic lineageEukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › fabids › Fabales › Fabaceae › Papilionoideae › Trifolieae › Medicago

Protein attributes

Sequence length364 AA.
Sequence statusComplete.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

2-hydroxyisoflavanone 4'-O-methyltransferase involved in the biosynthesis of the phytoalexin medicarpin. Has also an in vitro (+)-6a-hydroxymaackiain-3-0-methyltransferase activity, converting the pterocarpan 6a-hydroxymaackiain into pisatin. No activity with di- or trihydroxylated isoflavones, including daidzein and genistein, or with (-)-medicarpin and maackiain. The dual activity for either 3- or 4'-O-methylation depends upon substrate availability. Ref.1

Catalytic activity

S-adenosyl-L-methionine + a 4'-hydroxyisoflavone = S-adenosyl-L-homocysteine + a 4'-methoxyisoflavone.

S-adenosyl-L-methionine + 2,7,4'-trihydroxyisoflavanone = S-adenosyl-L-homocysteine + 2,7-dihydroxy-4'-methoxyisoflavanone.

Subunit structure

Homodimer. Ref.1

Sequence similarities

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

Biophysicochemical properties

Kinetic parameters:

KM=73.3 µM for 2,7,4'-trihydroxyisoflavanone Ref.1

KM=62.1 µM for 6a-hydroxymaackiain

KM=99.8 µM for S-adenosyl-L-methionine

Vmax=4.0 nmol/min/mg enzyme with 2,7,4'-trihydroxyisoflavanone as substrate

Vmax=17.9 nmol/min/mg enzyme with 6a-hydroxymaackiain as substrate

Vmax=23.9 nmol/min/mg enzyme toward S-adenosyl-L-methionine for the 4'-O-methyltransferase activity

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 364364Isoflavone 4'-O-methyltransferase
PRO_0000411977

Regions

Region206 – 2094S-adenosyl-L-methionine binding
Region230 – 2312S-adenosyl-L-methionine binding
Region250 – 2512S-adenosyl-L-methionine binding
Compositional bias96 – 994Poly-Glu

Sites

Active site2681Proton acceptor By similarity
Binding site2641S-adenosyl-L-methionine

Secondary structure

1 ................................................................ 364
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
Q29U70 [UniParc].

Last modified April 4, 2006. Version 1.
Checksum: C7C83C858A4BC9E5

FASTA36440,754
        10         20         30         40         50         60 
MAFSTNGSEE SELYHAQIHL YKHVYNFVSS MALKSAMELG IADAIHNHGK PMTLSELASS 

        70         80         90        100        110        120 
LKLHPSKVNI LHRFLRLLTH NGFFAKTIVK GKEGDEEEEI AYSLTPPSKL LISGKPTCLS 

       130        140        150        160        170        180 
SIVKGALHPS SLDMWSSSKK WFNEDKEQTL FECATGESFW DFLNKDSESS TLSMFQDAMA 

       190        200        210        220        230        240 
SDSRMFKLVL QENKRVFEGL ESLVDVGGGT GGVTKLIHEI FPHLKCTVFD QPQVVGNLTG 

       250        260        270        280        290        300 
NENLNFVGGD MFKSIPSADA VLLKWVLHDW NDEQSLKILK NSKEAISHKG KDGKVIIIDI 

       310        320        330        340        350        360 
SIDETSDDRG LTELQLDYDL VMLTMFLGKE RTKQEWEKLI YDAGFSSYKI TPISGFKSLI 


EVYP

« Hide

References

[1]"Structural basis for dual functionality of isoflavonoid O-methyltransferases in the evolution of plant defense responses."
Liu C.J., Deavours B.E., Richard S.B., Ferrer J.L., Blount J.W., Huhman D., Dixon R.A., Noel J.P.
Plant Cell 18:3656-3669(2006) [PubMed: 17172354] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, X-RAY CRYSTALLOGRAPHY (2.35 ANGSTROMS) OF 7-364 IN COMPLEX WITH SUBSTRATES, SUBUNIT.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ		AY942158 mRNA. Translation: AAY18581.1.

3D structure databases

PDBe
RCSB PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
1ZG3X-ray2.35A7-364[»]
1ZGAX-ray2.35A8-364[»]
1ZGJX-ray2.50A11-364[»]
1ZHFX-ray2.50A8-364[»]
ProteinModelPortalQ29U70.
SMRQ29U70. Positions 7-364.
ModBaseSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

InterProIPR016461. O-MeTrfase_COMT_euk.
IPR001077. O_MeTrfase_2.
IPR012967. Plant_MeTrfase_dimerisation.
IPR011991. WHTH_trsnscrt_rep_DNA-bd.
[Graphical view]
Gene3DG3DSA:1.10.10.10. Wing_hlx_DNA_bd. 1 hit.
PfamPF08100. Dimerisation. 1 hit.
PF00891. Methyltransf_2. 1 hit.
[Graphical view]
PIRSFPIRSF005739. O-mtase. 1 hit.
ProtoNetSearch...

Entry information

Entry nameI4OMT_MEDTR
AccessionPrimary (citable) accession number: Q29U70
Entry history
Integrated into UniProtKB/Swiss-Prot: July 27, 2011
Last sequence update: April 4, 2006
Last modified: January 25, 2012
This is version 31 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Relevant documents

PDB cross-references

Index of Protein Data Bank (PDB) cross-references

SIMILARITY comments

Index of protein domains and families

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