|ZFIN ID: ZDB-PUB-120314-17|
|Source:||BMC research notes 5(1): 134 (Journal)|
|Registered Authors:||Glasgow, Eric|
|PubMed:||22405347 Full text @ BMC Res. Notes|
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.