Reviewed, UniProtKB/Swiss-Prot Q9M1W4 (HMT2_ARATH)

Names and origin

Protein names

Recommended name:
    Homocysteine S-methyltransferase 2
    EC=2.1.1.10
Alternative name(s):
    S-methylmethionine:homocysteine methyltransferase 2
      Short name=SMM:Hcy S-methyltransferase 2
      Short name=AtHMT-2

Gene names

Name:	HMT-2
Ordered Locus Names:	At3g63250
ORF Names:	F16M2.100

Organism

Arabidopsis thaliana (Mouse-ear cress) [Complete proteome]

Taxonomic identifier

3702 [NCBI]

Taxonomic lineage

Eukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › eurosids II › Brassicales › Brassicaceae › Arabidopsis

Protein attributes

Sequence length	333 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Catalyzes methyl transfer from S-methylmethionine (SMM) to adenosyl-L-homocysteine (AdoMet). SMM degradation (by HMT-1, HMT-2 and HMT-3) and biosynthesis (by MMT1) constitute the SMM cycle in plants, which is probably required to achieve short term control of AdoMet level. Ref.4
Catalytic activity	S-adenosyl-L-methionine + L-homocysteine = S-adenosyl-L-homocysteine + L-methionine. Ref.1
Cofactor	Zinc Potential.
Subunit structure	Monomer. Ref.1
Tissue specificity	Expressed predominantly in roots. Expressed in rosette leaves, cauline leaves and developing seeds. Ref.4
Miscellaneous	In contrast to HMT-1, it is not inhibited by methionine.
Sequence similarities	Contains 1 Hcy-binding domain.
biophysicochemical properties	Kinetic parameters: KM=50 µM for S-methylmethionine KM=225 µM for (S,S)-AdoMet

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Methionine biosynthesis
Coding sequence diversity	Alternative splicing
Ligand	Metal-binding S-adenosyl-L-methionine Zinc
Molecular function	Methyltransferase Transferase
Technical term	Complete proteome
Gene Ontology (GO)
Biological process	S-methylmethionine cycle Inferred from mutant phenotype. Source: TAIR methionine biosynthetic process Ref.1 Inferred from direct assay. Source: TAIR
Molecular function	homocysteine S-methyltransferase activity Ref.1 Inferred from direct assay. Source: TAIR zinc ion binding Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Alternative products

This entry describes 1 isoform produced by alternative splicing. [Select]

Note: A number of isoforms are produced. According to EST sequences.

Isoform 1 (identifier: Q9M1W4-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 333	333	Homocysteine S-methyltransferase 2		PRO_0000114612
Regions
	Domain	8 – 327	320	Hcy-binding
Sites
	Metal binding	245	1	Zinc Potential
	Metal binding	312	1	Zinc Potential
	Metal binding	313	1	Zinc Potential
Experimental info
	Sequence conflict	103	1	T → C in AAF23822. Ref.1

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 [UniParc]. Last modified October 1, 2000. Version 1. Checksum: CB44D8F3BAC15D85	FASTA	333	36,451
	10 20 30 40 50 60 MTGNSFNSMK DFLKQTGGYA VIDGGLATEF ERHGADLNDP LWSAKCLVTS PHLIHTVHLD 70 80 90 100 110 120 YLEAGADIIS SASYQATIQG FEAKGFSREE SESLLKKSVE IATEARNSYY DKCGTSSSMD 130 140 150 160 170 180 DKILKKRPIL VAASVGSYGA YLADGSEYSG IYGDSITLEK LKDFHRRRLQ VLAESGADLI 190 200 210 220 230 240 AFETIPNKIE AQAFADLLEE GDVKIPGWFS FNSKDGVNVV SGDSIKECIS IAENCEKVVA 250 260 270 280 290 300 VGINCTPPRF IEGLVLEIEK VTSKPILVYP NSGESYDADR KEWVENTGVG DEDFVSYVEK 310 320 330 WMDAGVSLLG GCCRTTPTTI RAIHKRLVNR RSL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Characterization and functional expression of cDNAs encoding methionine-sensitive and -insensitive homocysteine S-methyltransferases from Arabidopsis." Ranocha P., Bourgis F., Ziemak M.J., Rhodes D., Gage D.A., Hanson A.D. J. Biol. Chem. 275:15962-15968(2000) [PubMed: 10747987] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], ENZYME ACTIVITY, SUBUNIT.
[2]	"Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana." Salanoubat M., Lemcke K., Rieger M., Ansorge W., Unseld M., Fartmann B., Valle G., Bloecker H., Perez-Alonso M., Obermaier B., Delseny M., Boutry M., Grivell L.A., Mache R., Puigdomenech P., De Simone V., Choisne N., Artiguenave F. , Robert C., Brottier P., Wincker P., Cattolico L., Weissenbach J., Saurin W., Quetier F., Schaefer M., Mueller-Auer S., Gabel C., Fuchs M., Benes V., Wurmbach E., Drzonek H., Erfle H., Jordan N., Bangert S., Wiedelmann R., Kranz H., Voss H., Holland R., Brandt P., Nyakatura G., Vezzi A., D'Angelo M., Pallavicini A., Toppo S., Simionati B., Conrad A., Hornischer K., Kauer G., Loehnert T.-H., Nordsiek G., Reichelt J., Scharfe M., Schoen O., Bargues M., Terol J., Climent J., Navarro P., Collado C., Perez-Perez A., Ottenwaelder B., Duchemin D., Cooke R., Laudie M., Berger-Llauro C., Purnelle B., Masuy D., de Haan M., Maarse A.C., Alcaraz J.-P., Cottet A., Casacuberta E., Monfort A., Argiriou A., Flores M., Liguori R., Vitale D., Mannhaupt G., Haase D., Schoof H., Rudd S., Zaccaria P., Mewes H.-W., Mayer K.F.X., Kaul S., Town C.D., Koo H.L., Tallon L.J., Jenkins J., Rooney T., Rizzo M., Walts A., Utterback T., Fujii C.Y., Shea T.P., Creasy T.H., Haas B., Maiti R., Wu D., Peterson J., Van Aken S., Pai G., Militscher J., Sellers P., Gill J.E., Feldblyum T.V., Preuss D., Lin X., Nierman W.C., Salzberg S.L., White O., Venter J.C., Fraser C.M., Kaneko T., Nakamura Y., Sato S., Kato T., Asamizu E., Sasamoto S., Kimura T., Idesawa K., Kawashima K., Kishida Y., Kiyokawa C., Kohara M., Matsumoto M., Matsuno A., Muraki A., Nakayama S., Nakazaki N., Shinpo S., Takeuchi C., Wada T., Watanabe A., Yamada M., Yasuda M., Tabata S. Nature 408:820-822(2000) [PubMed: 11130713] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Columbia.
[3]	"Empirical analysis of transcriptional activity in the Arabidopsis genome." Yamada K., Lim J., Dale J.M., Chen H., Shinn P., Palm C.J., Southwick A.M., Wu H.C., Kim C.J., Nguyen M., Pham P.K., Cheuk R.F., Karlin-Newmann G., Liu S.X., Lam B., Sakano H., Wu T., Yu G. , Miranda M., Quach H.L., Tripp M., Chang C.H., Lee J.M., Toriumi M.J., Chan M.M., Tang C.C., Onodera C.S., Deng J.M., Akiyama K., Ansari Y., Arakawa T., Banh J., Banno F., Bowser L., Brooks S.Y., Carninci P., Chao Q., Choy N., Enju A., Goldsmith A.D., Gurjal M., Hansen N.F., Hayashizaki Y., Johnson-Hopson C., Hsuan V.W., Iida K., Karnes M., Khan S., Koesema E., Ishida J., Jiang P.X., Jones T., Kawai J., Kamiya A., Meyers C., Nakajima M., Narusaka M., Seki M., Sakurai T., Satou M., Tamse R., Vaysberg M., Wallender E.K., Wong C., Yamamura Y., Yuan S., Shinozaki K., Davis R.W., Theologis A., Ecker J.R. Science 302:842-846(2003) [PubMed: 14593172] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. Strain: cv. Columbia.
[4]	"The S-methylmethionine cycle in angiosperms: ubiquity, antiquity and activity." Ranocha P., McNeil S.D., Ziemak M.J., Li C., Tarczynski M.C., Hanson A.D. Plant J. 25:575-584(2001) [PubMed: 11309147] [Abstract] Cited for: PROBABLE FUNCTION OF SMM CYCLE, BIOPHYSICOCHEMICAL PROPERTIES, TISSUE SPECIFICITY.

Cross-references

Sequence databases
EMBLGenBankDDBJ	AF219223 Genomic DNA. Translation: AAF23822.1. AL138648 Genomic DNA. Translation: CAB86426.1. AF428402 mRNA. Translation: AAL16170.1. BT010165 mRNA. Translation: AAQ22634.1.
IPI	IPI00534315.
PIR	T48114. T51939.
RefSeq	NP_191884.1.
UniGene	At.21554
3D structure databases
ModBase	Search...
Proteomic databases
PRIDE	Q9M1W4.
Genome annotation databases
GeneID	825500.
GenomeReviews	Gene locus AT3G63250 in contig BA000014_GR.
KEGG	ath:AT3G63250.
NMPDR	fig|3702.1.peg.17715.
Organism-specific databases
TAIR	At3g63250.
Phylogenomic databases
OMA	Q9M1W4. IRAIYRT.
Gene expression databases
ArrayExpress	Q9M1W4.
Family and domain databases
InterPro	IPR003726. S_MeTrfase. [Graphical view]
Gene3D	G3DSA:3.20.20.330. S_methyl_trans. 1 hit.
Pfam	PF02574. S-methyl_trans. 1 hit. [Graphical view]
PROSITE	PS50970. HCY. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

HMT2_ARATH

Accession

Primary (citable) accession number: Q9M1W4
Secondary accession number(s): Q9SDL6

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 19, 2004
Last sequence update:	October 1, 2000
Last modified:	June 16, 2009
This is version 40 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

PPAP (Plant Proteome Annotation Project)