Publication details
Dramatic Differencesin the Electrochemical and Spectral Behavior of Hexameric and Heptameric DNA Fragments
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| Year of publication | 2020 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Dramatic electrochemical and spectroscopic differences,caused by the loss of the adenine nucleotide residing in the middle of the heptamer d(GCGAAGC), were revealed[1].Basedon comparative voltammetric, circular dichroic and electrophoretic studiesof the hexamer (Hx) -d(GCGAGC) and the heptamer (Hp) -d(GCGAAGC) we illustrate how a single nucleotide sequence and a neighbouring nucleotide species in ODNs strongly affect their secondary structure.Dedicated studies suggest that the heptamer (Hp) possesses a hairpin structure, whereas the hexamer (Hx) appears to be rather a duplex. Both of the structures exhibited completely different adsorption behaviorat the hanging mercury drop electrode, and this factor was readily confirmed by means of elimination voltammetry with linear scan (EVLS)[2].We established that the Hp hairpin (~ -1300 mV), compared to the Hx duplex (~ -1360 mV), is the thermodynamically favored electron acceptor. The adsorption isotherms were constructed based on the voltammetric peak height values, reflecting the reduction of the adenine (A) and cytosine (C) moieties as well as the oxidation of the 7,8-dihydroguanine (7,8-DHG) moieties[3,4]. The comparative spectroscopic and electrochemical studies of heptameric and hexameric DNA fragments showed that not only the Hx structure but also the Hp structure (denoted as a thermodynamically very stable formation in solutions [5]) is vulnerable by an electrode field.Finally, as revealed by both the spectroscopic and electrochemical results, Hx forms a bimolecular antiparallel homo-duplex carrying both Watson–Crick base pairs (CG or GC) and mismatched edge-to-edge base pairs (GA or AG). |
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