Hemiprotonated C – C+ base pairing investigated by electrochemical and spectral methods
| Authors | |
|---|---|
| Year of publication | 2013 |
| Type | Article in Proceedings |
| Conference | Bioelectrochemistry 2013, 12th Topical Meeting of the ISE and XXII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society |
| MU Faculty or unit | |
| Citation | |
| Field | Physical chemistry and theoretical chemistry |
| Keywords | oligonucleotides;ODN;cytosine;i-motifs;linear sweep voltammetry;LSV;elimination voltammetry;EVLS;circular dichroism;UV/Vis spectrophotometry |
| Description | It is generally known that under slightly acidic pH conditions oligodeoxynucleotides (ODNs) rich in cytosine (C) can form i-motifs (intercalated hemiprotonated C – C+ base pairing). These structures can be responsible for i-tetraplexes in both centromeric and telomeric regions of human chromosomes. There are speculations that the presence of i-motif structures correlates with the expansion of the triplet repeat sequences associated with neurological disorders [1-3]. The present work deals with the electrochemical and spectral investigation of short ODNs containing different numbers of C. Using linear sweep voltammetry (LSV) and elimination voltammetry with linear scan (EVLS) we studied not only the effect of the number of C in the ODNs chain on the reduction signals in buffered and non-buffered solutions but also the effect of pH and ionic strength. The reduction C peaks, recorded at the mercury electrode in the potential range from –1.1 V to –1.7 V vs. Ag/AgCl/3MKCl, are influenced by ODN conformation changes which were confirmed by circular dichroism and UV-Vis spectra. The intermolecular or intramolecular folded i-motif structures were found for all ODNs except dC3. The electrochemical and spectral experiments were completed with the results of gel electrophoresis of ODNs on PAGE. |
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