ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P139. The Methylation of Monofunctional Dienplatin Affects Conformation
of DNA Adducts and Their Processing by DNA Polymerases
O. Novakova a , J. Malina a , G. Natile b , V. Brabec a
a
Institute of Biophysics AS CR v.v.i., Kralovopolska 135, 612 65, Brno, Czech Republic
e-mail: olga@ibp.cz
b
Department Farmaco-Chimico, University of Bari, Via E. Orabona 4, I-70125, Bari, Italy
To learn more about structure-function relationship of platinum complexes and factors affecting inhibition by
these compounds of DNA replication, we investigated DNA polymerization using DNA templates sitespecifically
modified by the adducts of monofunctional [PtCl(dien)]+, dien = diethylenetriamine (dienplatin,
dienPt) and its methylated derivatives in three sequence contexts. These adducts were characterized structurally
and analyzed for their ability to affect DNA polymerization using two DNA polymerases which differed in
processivity and fidelity. We found that character of DNA distortions induced by the adducts of the
monofunctional complexes was dependent on the sequence context and extent of the methylation. The adducts of
the methylated complexes strongly inhibited DNA polymerases in a sequence dependent manner whereas those
of nonmethylated dienPt did not. Also interestingly, the polymerases discriminated between Me3dienPt and
Me5dienPt adducts and the adducts of Me5dienPt strongly inhibited a single nucleotide misincorporation
opposite the platinated nucleotide. The results indicate that the bulkiness of DNA adducts of monofunctional
platinum complexes is a key factor in mechanism of the blockage of DNA polymerases.
Acknowledgement: This research was supported by Grant Agency of the Czech Republic (Grant 203/06/1239)
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