44 Circular dichroism (CD) studies of the interaction between G-quadrulexes/I-motif with saffron secondary active metabolites

Telomeric DNA contains some unique secondary structures, such as G-quadruplex and I-motif. These structures may be stabilized or changed by binding to specific proteins or small molecules. In continuation of our previous studies on the interaction between crocin and crocetin, as the natural C20 carotenoids, and picrocrocin and safranal, as the natural monoterpene aldehydes, obtained from saffron and DNA (Bathaie et al., 2007; Hoshyar et al., 2008), herein, we report the in vitro effect of these saffron metabolites on the mentioned structures (Hoshyar et al., 2012). Circular dichroism (CD) data indicate that crocetin has higher affinity for these structures. Safranal and crocin induce little change in the I-motif and G-quadruplex, respectively. The molecular docking confirms the experimental data and indicates the minor groove binding of ligands with G-quadruplex. Effects of these ligands on the stability of these structures is studied using some other techniques and determination of thermodynamic parameters.