ZFIN ID: ZDB-PUB-120314-17
Characterization of magnesium requirement of human 5' -tyrosyl DNA phosphodiesterase mediated reaction
Adhikari, S., Karmahapatra, S.K., Karve, T.M., Bandyopadhyay, S., Woodrick, J., Manthena, P.V., Glasgow, E., Byers, S., Saha, T., and Uren, A.
Date: 2012
Source: BMC research notes   5(1): 134 (Journal)
Registered Authors: Glasgow, Eric
Keywords: none
MeSH Terms:
  • Animals
  • Calcium/metabolism
  • Cell Extracts/chemistry
  • DNA/metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Embryo, Nonmammalian/embryology
  • Embryo, Nonmammalian/enzymology*
  • Enzyme Activation
  • Escherichia coli/genetics
  • Fish Proteins/isolation & purification
  • Fish Proteins/metabolism*
  • Humans
  • MCF-7 Cells
  • Magnesium/metabolism*
  • Manganese/metabolism*
  • Nuclear Proteins/genetics
  • Nuclear Proteins/isolation & purification
  • Nuclear Proteins/metabolism*
  • Oligonucleotides/metabolism
  • Recombinant Proteins/genetics
  • Recombinant Proteins/isolation & purification
  • Recombinant Proteins/metabolism
  • Tissue Extracts/chemistry
  • Transcription Factors/genetics
  • Transcription Factors/isolation & purification
  • Transcription Factors/metabolism*
  • Zebrafish/embryology
  • Zebrafish/metabolism*
  • Zinc/metabolism
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.