PMID:12654914
| Citation |
Kwon, K, Cao, C and Stivers, JT (2003) A novel zinc snap motif conveys structural stability to 3-methyladenine DNA glycosylase I. J. Biol. Chem. 278:19442-6 |
|---|---|
| Abstract |
The Escherichia coli 3-methyladenine DNA glycosylase I (TAG) is a DNA repair enzyme that excises 3-methyladenine in DNA and is the smallest member of the helix-hairpin-helix (HhH) superfamily of DNA glycosylases. Despite many studies over the last 25 years, there has been no suggestion that TAG was a metalloprotein. However, here we establish by heteronuclear NMR and other spectroscopic methods that TAG binds 1 eq of Zn2+ extremely tightly. A family of refined NMR structures shows that 4 conserved residues contributed from the amino- and carboxyl-terminal regions of TAG (Cys4, His17, His175, and Cys179) form a Zn2+ binding site. The Zn2+ ion serves to tether the otherwise unstructured amino- and carboxyl-terminal regions of TAG. We propose that this unexpected "zinc snap" motif in the TAG family (CX(12-17)HX(approximately 150)HX(3)C) serves to stabilize the HhH domain thereby mimicking the functional role of protein-protein interactions in larger HhH superfamily members. |
| Links |
PubMed Online version:10.1074/jbc.M300934200 |
| Keywords |
Amino Acid Sequence; Bacteria/enzymology; Binding Sites; Cobalt; Conserved Sequence; Cysteine/metabolism; DNA Glycosylases; DNA Repair; Escherichia coli/enzymology; Histidine/metabolism; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Sequence Data; Molecular Structure; N-Glycosyl Hydrolases/chemistry; N-Glycosyl Hydrolases/metabolism; Sequence Alignment; Spectrophotometry, Atomic; Spectrophotometry, Ultraviolet; Zinc/chemistry; Zinc/metabolism; Zinc Fingers |
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