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Cijaninske boje su važne fluorescentne probe za nukleinske kiseline koje pokazuju veliki afinitet za vezanje prema DNA i RNA. Sintetizirani su konjugati cijaninske boje i aminokiseline krenuvši od polaznih spojeva: benzotiazola, lepidina i DL-propargilglicina. Ključan korak sinteze je bakrom katalizirana cikloadicija azida i alkina (tzv. „klik“ reakcija). Dobivena su tri spoja s etilnim, propilnim i butilnim veznim lancem između cijaninskog i triazolnog dijela konjugata. Ispitane su interakcije dobivenih spojeva s različitim polinukleotidima, koristeći standardne spektrofotometrijske metode UV/Vis-spektroskopije, termičke denaturacije i fluorimetrije. Nove aminokiselinske boje, iako intrinzično ne-fluorescentne, daju snažan fluorimetrijski odgovor nakon vezanja na dvolančane (ds)-DNA ili (ds)-RNA, pri čemu se selektivnost u odgovoru emisije različitih polinukleotidnih sekundarnih struktura kontrolira dužinom poveznice. Novosintetizirani konjugati se različito vežu za polinukleotide različite sekundarne strukture, uz odgovarajuće različite intenzitete fluorescencijske emisije. Spektrofotometrijska ispitivanja upućuju većinom na vezanje cijaninske boje u utore DNA/RNA, no neki derivati u određene DNA/RNA interkaliraju. Cyanine dyes are important fluorescence probes for nucleic acids exhibiting high affinity for binding to DNA and RNA. Conjugates of cyanine dye and amino acid were synthesized from the starting compounds: benzothiazole, lepidine and DL-propargylglycine. The key step of synthesis is copper-catalyzed cycloaddition of azide and alkynes, a so called “click” reaction. Three compounds were obtained with the ethyl, propyl and butyl linkers between the cyanine part and the triazole part of the conjugate. The interactions of the conjugates with different polynucleotides were investigated using standard spectroscopic methods of UV/Vis spectroscopy, thermal denaturation experiments and fluorescence. Novel amino acid dyes, although intrinsically non-fluorescent, give rise to strong fluorimetric response upon binding to double-stranded (ds)-DNAs or (ds)-RNA, whereby selectivity in emission response to various polynucleotide secondary structures is controlled by linker length. Mostly, new compounds bind to the polynucleotide minor groove, while in some specific cases intercalation into DNA/RNA was observed. |
