Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-31238
Hardeland, U; Bentele, M; Jiricny, J; Schär, P (2003). The versatile thymine DNA-glycosylase: a comparative characterization of the human, Drosophila and fission yeast orthologs. Nucleic Acids Research, 31(9):2261-2271.
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Human thymine-DNA glycosylase (TDG) is well known to excise thymine and uracil from G.T and G.U mismatches, respectively, and was therefore proposed to play a central role in the cellular defense against genetic mutation through spontaneous deamination of 5-methylcytosine and cytosine. In this study, we characterized two newly discovered orthologs of TDG, the Drosophila melanogaster Thd1p and the Schizosaccharomyces pombe Thp1p proteins, with an objective to address the function of this subfamily of uracil-DNA glycosylases from an evolutionary perspective. A systematic biochemical comparison of both enzymes with human TDG revealed a number of biologically significant facts. (i) All eukaryotic TDG orthologs have broad and species-specific substrate spectra that include a variety of damaged pyrimidine and purine bases; (ii) the common most efficiently processed substrates of all are uracil and 3,N4- ethenocytosine opposite guanine and 5-fluorouracil in any double-stranded DNA context; (iii) 5-methylcytosine and thymine derivatives are processed with an appreciable efficiency only by the human and the Drosophila enzymes; (iv) none of the proteins is able to hydrolyze a non-damaged 5'-methylcytosine opposite G; and (v) the double strand and mismatch dependency of the enzymes varies with the substrate and is not a stringent feature of this subfamily of DNA glycosylases. These findings advance our current view on the role of TDG proteins and document that they have evolved with high structural flexibility to counter a broad range of DNA base damage in accordance with the specific needs of individual species.
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|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Institute of Molecular Cancer Research
07 Faculty of Science > Institute of Molecular Cancer Research
|DDC:||570 Life sciences; biology|
|Deposited On:||09 Jul 2010 07:19|
|Last Modified:||27 Nov 2013 21:57|
|Publisher:||Oxford University Press|
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