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"Active site and complete sequence of the suicidal methyltransferase that counters alkylation mutagenesis." |
Demple B, Sedgwick B, Robins P, Totty N, Waterfield MD, Lindahl T |
Published May 1, 1985 in Proc Natl Acad Sci U S A volume 82 .
Pubmed ID: 3887409
Abstract:
| The inducible resistance to alkylation mutagenesis and killing in Escherichia coli (the adaptive response) is controlled by the ada gene. The Ada protein acts both as a positive regulator of the response and as a DNA repair enzyme, correcting premutagenic O6-alkylguanine in DNA by suicidal transfer of the alkyl group to one of its own cysteine residues. We have determined the DNA sequence of the cloned ada+ gene and its regulatory region. The data reveal potential sites of ada autoregulation. Amino acid sequence determinations show that the active center for the O6-methylguanine-DNA methyltransferase is located close to the polypeptide COOH terminus and has the unusual sequence -Pro-Cys-His-, preceded by a very hydrophobic region. These same structural features are present at the active site of thymidylate synthase, suggesting a common chemical mechanism for activation of the cysteine. |
This publication refers to following REPAIRtoire entries:
| Proteins |
Last modification of this entry: Oct. 6, 2010
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