Protein Family Models

This entry corresponds to the N-terminal alpha helical domain of the HemK protein. HemK is a methyltransferase enzyme that carries out the methylation of the N5 nitrogen of the glutamine found in the conserved GGQ motif of class-1 release factors [3]. [1]. 15223314. Structural characterization and comparative phylogenetic analysis of Escherichia coli HemK, a protein (N5)-glutamine methyltransferase. Yang Z, Shipman L, Zhang M, Anton BP, Roberts RJ, Cheng X;. J Mol Biol. 2004;340:695-706. [2]. 16364916. Molecular basis for bacterial class I release factor methylation by PrmC. Graille M, Heurgue-Hamard V, Champ S, Mora L, Scrima N, Ulryck N, van Tilbeurgh H, Buckingham RH;. Mol Cell. 2005;20:917-927. [3]. 12741815. Structures along the catalytic pathway of PrmC/HemK, an N5-glutamine AdoMet-dependent methyltransferase. Schubert HL, Phillips JD, Hill CP;. Biochemistry. 2003;42:5592-5599. [4]. 18247349. A novel mode of dimerization via formation of a glutamate anhydride crosslink in a protein crystal structure. Agarwal R, Burley SK, Swaminathan S;. Proteins. 2008;71:1038-1041. (from Pfam)

Date:

2024-10-16

This family appears to be a methyltransferase domain. (from Pfam)

Date:

2024-08-14

This domain is found in ribosomal RNA small subunit methyltransferase C (eg Swiss:P44453) as well as other methyltransferases (eg Swiss:Q53742). (from Pfam)

Date:

2024-08-14

Members of this protein family are PrmC, a protein once thought to be involved in heme biosynthesis (and ibe once called HemK), but now recognized to be a protein-glutamine methyltransferase that modifies the peptide chain release factors. All members of the seed alignment are encoded next to the release factor 1 gene (prfA) and confirmed by phylogenetic analysis. SIMBAL analysis (PMID:20102603) shows the motif [LIV]PRx[DE]TE (in Escherichia coli, IPRPDTE) confers specificity for the release factors rather than for ribosomal protein L3.

Gene:

prmC

Date:

2023-12-19

N5-glutamine methyltransferase family protein such as peptide chain release factor N(5)-glutamine methyltransferase, which modifies the glutamine residue in the universally conserved glycylglycylglutamine (GGQ) motif of peptide chain release factor, resulting in almost complete loss of release activity

Date:

2024-08-09

The gene hemK from E. coli was found to contribute to heme biosynthesis and originally suggested to be protoporphyrinogen oxidase (Medline 95189105). Functional analysis of the nearest homolog in Saccharomyces cerevisiae, YNL063w, finds it is not protoporphyrinogen oxidase and sequence analysis suggests that HemK homologs have S-adenosyl-methionine-dependent methyltransferase activity (Medline 99237242). Homologs are found, usually in a single copy, in nearly all completed genomes, but varying somewhat in apparent domain architecture. Both E. coli and H. influenzae have two members rather than one. The members from the Mycoplasmas have an additional C-terminal domain.

Date:

2021-04-27