In-silico modeling studies of G-quadruplex with soy isoflavones having anticancerous activity.

Telomere forms t-loop and G-quadruplex as the protective structure and the formation of these structures hinder the telomerase enzyme action. The binding affinities of ligand which stabilize the G-quadruplex represent good correlation with telomerase inhibition depicted in the anti-cancerous action. Most of the potent G-quadruplex stabilizing compounds suffer from the poor drug like properties. Herein, natural dietary compounds isoflavones were taken for the theoretical study to examine their stabilizing effect on G-quadruplex structure. The experimental G-quadruplex complexes were reproduced to obtain and validate the theoretical parameters. The obtained theoretical binding energies are in significant correlation with the experimental data. Analysis of binding shows isoflavones to be groove binders, and differential nature of quadruplex grooves might be beneficial in the selectivity aspects. Among all, derrubone was found to have better selectivity as well as affinity for the G-quadruplex comparable to well known ligand TMPyP4. The GBSA rescoring result enlightens the various interaction terms involved in the binding process. Cumulative stabilizing effects coming from VDW, ES, and GB energy terms attest to optimal binding of derrubone molecule which can be considered as a lead for the higher phases of drug designing. These findings are of great value in terms of unexplored groove binding modes and the studied natural compounds might be helpful to direct the focus of synthetic chemists in designing of new generation of antitumor agents.