Theoretical and experimental study of charge transfer through DNA:
impact of mercury attached to mismatched base pairs
Irena Kratochvílová1,2*,,
Martin Golan1,3, Martin Vala4, Miroslava
Špérová4, Martin Weiter4, Ondřej
Páv5*, Jakub Šebera1,5, Ivan Rosenberg5, Vladimír Sychrovský5
1Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i, Na Slovance 2, CZ-182 21, Prague 8, Czech Republic
2Faculty of Nuclear Physics and Physical Engineering, Czech Technical University in Prague, Zikova 1, 160 00 Prague 6, Czech Republic
3Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
4Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic
5Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo náměstí 2, CZ-16610 Prague 6, Czech Republic
DNA-Hg complexes play an important role in
sensing of defects in DNA or presence of Hg in the environment. A fundamental way
of characterizing DNA-Hg complexes is investigating the way electric charge is
transferred through the complex. The main goal of this contribution was to investigate the impact of
mercury metal cation that links two thymine bases in DNA T-T mismached
base pair (T-Hg-T) on charge transfer through the DNA molecule. We compared the charge transfer efficiencies in standard DNA, DNA with mismatched T-T base pairs and
DNA with T-Hg(II)-T base pair. For this purpose we measured the temperature dependence of steady-state
fluorescence and UV-VIS
of the DNA molecules. The experimental results were confronted with the
results obtained employing theoretical DFT methods. In our case it was namely the spatial overlap
of bases that substantially influenced the calculated charge transfer rates,
and the overlap of bases was notably affected by the presence of Hg(II) linkage in the T-T mismatch. Our investigation of
the metallo DNA duplex provides the basis for design
of metal-conjugated nucleic acid nanomaterials.