El-Sayed, Ahmed A.3; Pedersen, Erik Bjerregaard5; Khaireldin, Nahid A.4
1 Department of Physics, Chemistry and Pharmacy, Faculty of Science, SDU2 NAC, Institut for Fysik og Kemi, Department of Physics, Chemistry and Pharmacy, Faculty of Science, SDU3 Syddansk Universitet4 National Research Center5 Department of Physics, Chemistry and Pharmacy, Faculty of Science, SDU
Certain cytosine-rich (C-rich) DNA sequences can fold into secondary structures as four-stranded i-motifs with hemiprotonated base pairs. Here we synthesized C-rich TINA-intercalating oligonucleotides by inserting a nonnucleotide pyrene moiety between two C-rich regions. The stability of their i-motif structures was studied by using UV melting temperature measurements and circular dichroism spectra at different pH values under noncrowding and crowding conditions (20% poly(ethylene glycol)). When TINA ((R)-3-((4-(1-pyrenylethynyl)benzyl)oxy) propane-1,2-diol) is inserted, the oligonucleotides could form an i-motif at a higher pH than observed for the corresponding wildtype oligonucleotide.
Nucleosides, Nucleotides and Nucleic Acids, 2012, Vol 31, p. 872-879