Molecular docking studies on binding specificity of 3,6- and 2,7-carbazoles with DNA duplexes

Molecular docking is a widely used computational technique used to find the probabilistic binding sites of drugs in the vicinity of macromolecules. The drugs produce their working effect only when they bind and interact with the target macromolecule. The potential drugs can only be identified by their relative binding affinities and corresponding binding modes. Availability of huge numbers of such drugs has made the estimation of their relative potency, a difficult task. In the present work, carbazoles (3,6 and 2,7) and their analogs were studied for their DNA binding abilities using molecular docking calculations. Since the docked ligands had planar structures, it allowed them to adopt crescent shape and thus minor groove binding with DNA was preferred by all. However, it was found that a single molecule (Mol-6) (2,7-carbazole) showed promising results with all the selected DNA sequences also its results were exactly verified with those in the reported literature and therefore it can be said that its in-vivo studies could possibly produce some exciting results. This study also revealed that DNA binding energies of 3,6- and 2,7-carbazoles followed the same trend as their thermal melting values.