Hairpin structures of DNA oligomers investigated by electrochemical and spectral methods


                                          Iveta Pilařová


Abstract


Nowadays, the great attention is devoted to the electrochemical study of DNA and RNA oligomers,
forming hairpin or hairpin – like structures in the dependence on the number of bases in the chain.

Hairpins, consisting of single-stranded loop and base – paired stem regions and naturally occuring
not only in single-stranded DNAs and RNAs but also in double – stranded DNAs, are very important in
many biological processes. They play a crucial role in expansion events of triplet repeat expansion
associated with neurodegenerative diseases, such as fragile chromosome X syndrome, Huntington’s
disease, Friedreich’s ataxia or myoclonic epilepsy. The shortest and most stable hairpin is formed
by the DNA heptamer d(GCGAAGC). This sequence is found in replication origins of phage ФX 174^ and
herpes simplex virus, in a promoter region of an Escherichia coli heat-shock gene, and in rRNA
genes.

The aim of our contribution is the investigation of DNA heptamers d(GCGAAGC); d(GCCCCGC);
d(GCGGGGC); d(GCAAAGC) and d(GCTTTGC) with different trinucleotide sequences in loop using cyclic
voltammetry (resp. linear sweep voltammetry) integrated with elimination voltammetry with linear
scan (EVLS). The conformational changes of DNA heptamers studied will be confirmed by circular
dichroism spectra and UV/VIS thermal denaturation.