1adn
From Proteopedia
SOLUTION STRUCTURE OF THE DNA METHYLPHOSPHOTRIESTER REPAIR DOMAIN OF ESCHERICHIA COLI ADA
Structural highlights
Function[ADA_ECOLI] Is involved in the adaptive response to alkylation damage in DNA caused by alkylating agents. Repairs O6-methylguanine and 04-methylthymine residues in alkylated DNA by a direct and irreversible transfer of the methyl group from the base to one of its own cysteine residues (Cys-321). Also specifically repairs the Sp diastereomer of DNA methylphosphotriester lesions by the same mechanism, although the methyl transfer occurs onto a different cysteine residue (Cys-38). Can not demethylate the other diastereomer, Rp-methylphosphotriester.[1] The methylation of Ada by methylphosphotriesters in DNA leads to its activation as a transcriptional regulator that activates the transcription of its own gene, ada, and other alkylation resistance genes, alkA, alkB and aidB.[2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe Escherichia coli Ada protein repairs methyl phosphotriesters in DNA by direct, irreversible methyl transfer to one of its own cysteine residues. The methyl-transfer process appears to be autocatalyzed by coordination of the acceptor residue, Cys-69, to a tightly bound zinc ion. Upon methyl transfer, Ada acquires the ability to bind DNA sequence-specifically and thereby to induce genes that confer resistance to methylating agents. The solution structure of an N-terminal 10-kDa fragment of Ada, which retains zinc binding and DNA methyl phosphotriester repair activities, was determined using multidimensional heteronuclear nuclear magnetic resonance techniques. The structure reveals a zinc-binding motif unlike any observed thus far in transcription factors or zinc-containing enzymes and provides insight into the mechanism of metalloactivated DNA repair. Solution structure of the DNA methyl phosphotriester repair domain of Escherichia coli Ada.,Myers LC, Verdine GL, Wagner G Biochemistry. 1993 Dec 28;32(51):14089-94. PMID:8260490[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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