SUPERFAMILY 1.73 HMM library and genome assignments server


Homocysteine S-methyltransferase superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   Alpha and beta proteins (a/b) [ 51349] (141)
  Mainly parallel beta sheets (beta-alpha-beta units)
Fold:   TIM beta/alpha-barrel [ 51350] (33)
  contains parallel beta-sheet barrel, closed; n=8, S=8; strand order 12345678
the first seven superfamilies have similar phosphate-binding sites
Superfamily:   Homocysteine S-methyltransferase [ 82282]
Families:   Homocysteine S-methyltransferase [ 82283] (2)
  Pfam 02574


Superfamily statistics
Genomes (961) UniProt 15.0 PDB chains (SCOP 1.73)
Domains 1,596 1,478 3
Proteins 1,595 1,477 3


Functional annotation
General category Metabolism
Detailed category Transferases

Function annotation of SCOP domain superfamilies
InterPro annotation
Cross references IPR003726 SSF82282 Protein matches
Abstract S-methylmethionine: homocysteine methyltransferase from Escherichia coli accepts selenohomocysteine as a substrate. S-methylmethionine is an abundant plant product that can be utilised for methionine biosynthesis [PubMed9882684]. 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 [PubMed9013615]. Betaine--homocysteine S-methyltransferase converts betaine and homocysteine to dimethylglycine and methionine, respectively. This reaction is also required for the irreversible oxidation of choline [PubMed8798461].

InterPro database

PDBeMotif information about ligands, sequence and structure motifs
Cross references PDB entries
Ligand binding statistics
Nucleic-acid binding statistics
Occurrence of secondary structure elements
Occurrence of small 3D structural motifs

PDBeMotif resource

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Internal database links

Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level.


Alignments of sequences to 3 models in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.


Browse and view proteins in genomes which have different domain combinations including a Homocysteine S-methyltransferase domain.


Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.


Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.

There are 3 hidden Markov models representing the Homocysteine S-methyltransferase superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.


Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Internal database links ]