Characterization of magnesium requirement of human 5'-tyrosyl DNA phosphodiesterase mediated reaction.
Characterization of magnesium requirement of human 5'-tyrosyl DNA phosphodiesterase mediated reaction.
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DOI：
10.1186/1756-0500-5-134
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发表时间：
2012-03-09
影响因子：
1.8
通讯作者：
Uren A
中科院分区：
文献类型：
--
作者：
Adhikari S;Karmahapatra SK;Karve TM;Bandyopadhyay S;Woodrick J;Manthena PV;Glasgow E;Byers S;Saha T;Uren A
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. 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. These results altogether reveal the optimal Mg2+ requirement in hTDP2 mediated reaction.
