Computational Modeling of Interaction between Camptothecin and DNA Base pairs

Understanding the physicochemical interaction between the novel drug Camptothecin (CTTC) and its biological receptor DNA is very important. Molecular modeling on the complex formed between CTTC and DNA presented this complex to be fully capable of participating in the formation of a stable intercalation site. The molecular geometries of CTTC and DNA bases were optimized with the aid of B3LYP/6-31G* method. Properties of the isolated intercalator and its stacking interactions with adenine··· thymine (AT) and guanine··· cytosine (GC) nucleic acid base pairs were studied with the DFTB method. Interaction energies of drug···base pair complexes were found to be-6.65 and-9.71 kcal/mol for AT··· CTTC and GC··· CTTC, respectively.