1. Characterization of magnesium requirement of human 5'-tyrosyl DNA phosphodiesterase mediated reaction
- Author
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Adhikari Sanjay, Karmahapatra Soumendra K, Karve Tejaswita M, Bandyopadhyay Sanjona, Woodrick Jordan, Manthena Praveen V, Glasgow Eric, Byers Stephen, Saha Tapas, and Uren Aykut
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Medicine ,Biology (General) ,QH301-705.5 ,Science (General) ,Q1-390 - Abstract
Abstract Background Topo-poisons can produce an enzyme-DNA complex linked by a 3'- or 5'-phosphotyrosyl covalent bond. 3'-phosphotyrosyl bonds can be repaired by tyrosyl DNA phosphodiesterase-1 (TDP1), an enzyme known for years, but a complementary human enzyme 5'-tyrosyl DNA phosphodiesterase (hTDP2) that cleaves 5'-phosphotyrosyl bonds has been reported only recently. Although hTDP2 possesses both 3'- and 5'- tyrosyl DNA phosphodiesterase activity, the role of Mg2+ in its activity was not studied in sufficient details. Results In this study we showed that purified hTDP2 does not exhibit any 5'-phosphotyrosyl phosphodiesterase activity in the absence of Mg2+/Mn2+, and that neither Zn2+ or nor Ca2+ can activate hTDP2. Mg2+ also controls 3'-phosphotyrosyl activity of TDP2. In MCF-7 cell extracts and de-yolked zebrafish embryo extracts, Mg2+ controlled 5'-phosphotyrosyl activity. This study also showed that there is an optimal Mg2+ concentration above which it is inhibitory for hTDP2 activity. Conclusion These results altogether reveal the optimal Mg2+ requirement in hTDP2 mediated reaction.
- Published
- 2012
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