Solution structure of the DNA methyl phosphotriester repair domain of Escherichia coli Ada.
Myers, L.C., Verdine, G.L., Wagner, G.(1993) Biochemistry 32: 14089-14094
- PubMed: 8260490 
- DOI: https://doi.org/10.1021/bi00214a003
- Primary Citation of Related Structures:  
1ADN - PubMed Abstract: 
The 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.
Organizational Affiliation: 
Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138.