Pfam 22.0 :: S-methyl

Pfam 22.0 :: S-methyl_trans
Description of the S-methyl_trans family

S-antigen <--	--> S1
S-methyl_trans

Accession number: PF02574
Homocysteine S-methyltransferase

This is a family of related homocysteine S-methyltransferases enzymes: 5-methyltetrahydrofolate--homocysteine S-methyltransferases also known EC:2.1.1.13, [2]; Betaine--homocysteine S-methyltransferase (vitamin B12 dependent), EC:2.1.1.5, [3]; and Homocysteine S-methyltransferase, EC:2.1.1.10, [1].

Description
S-methylmethionine: homocysteine methyltransferase from Escherichia coli accepts selenohomocysteine as a substrate. S-methylmethionine is an abundant plant product that can be utilized for methionine biosynthesis PUBMED:9882684. Human methionine synthase (5-methyltetrahydrofolate:L-homocysteine S-transmethylase; ) shares 53 and 63% identity with the E. coli and the presumptive Caenorhabditis elegans proteins, respectively, and contains all residues implicated in B12 binding to the E. coli protein PUBMED:9013615. Betaine--homocysteine S-methyltransferase () converts betaine and homocysteine to dimethylglycine and methionine, respectively. This reaction is also required for the irreversible oxidation of choline PUBMED:8798461.
Description text from InterPro entry IPR003726

Sequence information

Alignment

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Species distribution

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Literature References

[1]
S-methylmethionine metabolism in Escherichia coli.
Thanbichler M, Neuhierl B, Bock A;
J Bacteriol 1999;181:662-665.

[2]
Human methionine synthase. cDNA cloning, gene localization, and expression.
Chen LH, Liu ML, Hwang HY, Chen LS, Korenberg J, Shane B;
J Biol Chem 1997;272:3628-3634.

[3]
Purification, kinetic properties, and cDNA cloning of mammalian betaine-homocysteine methyltransferase.
Garrow TA;
J Biol Chem 1996;271:22831-22838.

Database References

SCOP	1lt8 (family)
INTERPRO	IPR003726

HMMER build information

	Pfam_ls [download HMM]	Pfam_fs [download HMM]
Gathering cutoff	-33.20 -33.20	25.00 25.00
Trusted cutoff	-32.70 -32.70	30.90 25.00
Noise cutoff	-33.30 -33.30	23.50 24.80
Build method of HMM	hmmbuild -F HMM_ls SEED hmmcalibrate --seed 0 HMM_ls	hmmbuild -f -F HMM_fs SEED hmmcalibrate --seed 0 HMM_fs

Pfam specific information

Author of entry	Bashton M, Bateman A
Type definition	Family
Source of seed members	COGs