Function and Biology

SOLUTION STRUCTURE OF THE DNA METHYLPHOSPHOTRIESTER REPAIR DOMAIN OF ESCHERICHIA COLI ADA

Source organism: Escherichia coli
Biochemical function: DNA binding
Biological process: DNA repair
Cellular component: not assigned

EC 2.1.1.63: Methylated-DNA--[protein]-cysteine S-methyltransferase

Reaction catalysed:
(1) DNA (containing 6-O-methylguanine) + protein L-cysteine = DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine. (2) DNA (containing 4-O-methylthymine) + protein L-cysteine = DNA (without 4-O-methylthymine) + protein S-methyl-L-cysteine.
Comments:
  • This protein is involved in the repair of methylated DNA.
  • Unlike EC 3.2.2.20 and EC 3.2.2.21, which remove the methylated base leaving an apurinic/apyrimidinic site, this enzyme transfers the methyl group from the methylated DNA to an internal cysteine residue, leaving an intact nucleotide.
  • Since the methyl transfer is irreversible, the enzyme can only catalyze a single turnover.
Systematic name:
DNA-6-O-methylguanine/DNA-4-O-methylthymine:[protein]-L-cysteine S-methyltransferase
Alternative Name(s):
  • O-6-methylguanine-DNA-alkyltransferase
  • 6-O-methylguanine-DNA methyltransferase
  • Ada (gene name)
  • Ogt (gene name)
  • MGT1 (gene name)
  • MGMT (gene name)

EC 2.1.1.n11: Methylphosphotriester-DNA--[protein]-cysteine S-methyltransferase

Reaction catalysed:
DNA (containing Sp-methylphosphotriester) + protein L-cysteine = DNA (without Sp-methylphosphotriester) + protein S-methyl-L-cysteine.
Comments:
  • This protein is involved in the repair of Sp diastereomers of DNA methylphosphotriester lesions.
  • This enzyme catalyzes only one turnover and therefore is not strictly catalytic.
  • The enzyme from the bacterium Escherichia coli also has the activity of EC 2.1.1.63 while the enzyme from Bacillus subtilis does not.
Systematic name:
DNA (containing Sp-methylphosphotriester):[protein] L-cysteine methyltransferase

GO terms

Biochemical function:
Biological process:
Cellular component:
  • not assigned

Sequence family

Pfam Protein family (Pfam)
PF02805
Domain description: Metal binding domain of Ada
Occurring in:
  1. Bifunctional transcriptional activator/DNA repair enzyme Ada
1 copy of Pfam domain PF02805 (Metal binding domain of Ada) in Bifunctional transcriptional activator/DNA repair enzyme Ada in PDB 1adn.

InterPro InterPro annotations
IPR035451
Domain description: Ada-like domain superfamily
Occurring in:
  1. Bifunctional transcriptional activator/DNA repair enzyme Ada
IPR004026
Domain description: Ada DNA repair, metal-binding
Occurring in:
  1. Bifunctional transcriptional activator/DNA repair enzyme Ada

Structure domain

CATH CATH domain
3.40.10.10
Class: Alpha Beta
Architecture: 3-Layer(aba) Sandwich
Topology: DNA Methylphosphotriester Repair Domain
Homology: DNA Methylphosphotriester Repair Domain
Occurring in:
  1. Bifunctional transcriptional activator/DNA repair enzyme Ada
1 copy of CATH domain 3.40.10.10 (DNA Methylphosphotriester Repair Domain) in Bifunctional transcriptional activator/DNA repair enzyme Ada in PDB 1adn.
SCOP SCOP annotation
57885
Class: Small proteins
Fold: Ada DNA repair protein, N-terminal domain (N-Ada 10)
Superfamily: Ada DNA repair protein, N-terminal domain (N-Ada 10)
Occurring in:
  1. Bifunctional transcriptional activator/DNA repair enzyme Ada
1 copy of SCOP domain 57885 (Ada DNA repair protein, N-terminal domain (N-Ada 10)) in Bifunctional transcriptional activator/DNA repair enzyme Ada in PDB 1adn.