Study of interactions of halogenated and non-halogenated cyanine derivatives with double-stranded DNA and RNA by spectrosopic methods

Cijaninske boje, kao poznate fluorescentne probe, pronalaze primjenu u specifičnoj detekciji nukleinskih kiselina. U okviru ovog diplomskog rada spektroskopski su okarakterizirane tri novosintetizirane cijaninske boje. Otopine spojeva posjeduju karakteristični UV/Vis spektar u valnom području od 220 nm do 600 nm. Intrinzično nefluorescentni cijanini, odlikuju se izrazitim fluorimetrijskim odgovorom uslijed vezanja na polinukleotide. Interakcije cijaninskih boja s dvolančanim polinukleotidima ispitane su standardnim spektrofotometrijskim metodama. Eksperimentima temperaturnog mekšanja i titracijama metodom cirkularnog dikroizma utvrđen je način vezanja spojeva na polinukleotide. Obradom fluorimetrijskih titracija pomoću Scatchardove jednadžbe metodom nelinearne regresije dobivene su konstante stabilnosti kompleksa cijaninskih boja s polinukleotidima. Cijanini su pokazali selektivnost u odnosu na na sekvencu i sekundarnu strukturu nukleinskih kiselina. Dobiveni rezultati ukazuju na mješovit način vezanja cijaninskih boja, u kojemu uz interkalaciju dolazi do vezanja dimera ili većih agregata u utore polinukleotidaCyanine dyes, as known fluorescent probes, find application in the specific detection of nucleic acids. Three newly synthesized cyanine dyes were characterized spectroscopically as part of this thesis. Aqueous solutions of compounds absorbed in the UV/Vis region 220-600 nm. Intrinsically non-fluorescent cyanines are characterized by a pronounced fluorimetric response upon binding to polynucleotides. Interactions of cyanine dyes with double-stranded polynucleotides were examined by standard spectrophotometric methods. The mode of binding of compounds to polynucleotides was determined by temperature melting experiments and CD titrations. Stability constants of the complexes with polynucleotides were obtained by processing fluorimetric titrations using the Scatchard equation. Cyanines have shown selectivity with respect to the sequence and secondary structure of nucleic acids. The obtained results also indicate a coexistence of several binding modes, in which intercalation is accompanied by binding of dimer or higher-order aggregates inside the polynucleotide grooves