title: G-quadruplex-based structural transitions in 15-mer DNA oligonucleotides varying in lengths of internal oligo(dG) stretches detected by voltammetric techniques.
abstract: Electrochemical methods, particularly when applied in connection with mercury-containing electrodes, are excellent tools for studying nucleic acids structure and monitoring structural transitions. We studied the effect of the length of the central (dG) n stretch (varying from 0 to 15 guanine residues) in 15-mer oligodeoxynucleotides (ODN, G0 to G15) on their electrochemical and interfacial behavior at mercury and carbon electrodes. The intensity of guanine oxidation signal at the carbon electrode (peak G(ox)) was observed to increase continuously with number of guanines between 0 and 15, with only a slight positive shift for ODNs with seven or more guanines in the central segment. Very different effects were observed when the peak G(HMDE) was measured at the mercury electrode. Intensity of the latter signal increased with number of guanines up to G5, and decreased sharply with further elongation of the (dG) n stretch. CD spectroscopy and electrophoresis experiments revealed formation of parallel intermolecular quadruplex structures for ODNs containing five or more G residues. Further measurements made by cyclic and alternating-current voltammetry revealed a strong influence of the ODN structure on their behavior at electrically charged surfaces.
authors.affiliation: Institute of Biophysics of the Academy of Sciences of the Czech Republic v.v.i., Kralovopolska 135, 61265, Brno, Czech Republic.
authors.forename: Pavlína
authors.initials: P
authors.lastname: Vidláková
authors.forename: Hana
authors.initials: H
authors.lastname: Pivoňková
authors.forename: Iva
authors.initials: I
authors.lastname: Kejnovská
authors.forename: Libuše
authors.initials: L
authors.lastname: Trnková
authors.forename: Michaela
authors.initials: M
authors.lastname: Vorlíčková
authors.forename: Miroslav
authors.initials: M
authors.lastname: Fojta
authors.forename: Luděk
authors.initials: L
authors.lastname: Havran
mesh_terms: D004247:DNA / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D054856:G-Quadruplexes; D009690:Nucleic Acid Conformation
chemical_list: D004247:DNA