2. Academic Validation
  3. Characterization of magnesium requirement of human 5'-tyrosyl DNA phosphodiesterase mediated reaction

Characterization of magnesium requirement of human 5'-tyrosyl DNA phosphodiesterase mediated reaction

  • BMC Res Notes. 2012 Mar 9;5:134. doi: 10.1186/1756-0500-5-134.
Sanjay Adhikari 1,  Soumendra K Karmahapatra,  Tejaswita M Karve,  Sanjona Bandyopadhyay,  Jordan Woodrick,  Praveen V Manthena,  Eric Glasgow,  Stephen Byers,  Tapas Saha,  Aykut Uren
Affiliations

Affiliation

  • 1 Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA. sa354@georgetown.edu
PMID: 22405347 DOI: 10.1186/1756-0500-5-134
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.

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