GHAZALA YUNUS^#, SEEMA SRIVASTAVA, VISHWAMBHAR DAYAL GUPTA

Department of Physics, Integral University, Kursi Road, Lucknow-226 026, India

Abstrac. In recent years, characterization of the thermodynamics of DNA-drug interactions has acquired considerable interest in rational drug design. The number and variety of techniques committed to evidence drug-DNA interactions is continuously growing. Recent analysis on structure and dynamics of nucleic acid suggest that the DNA helix undergoes conformational transition as function of salt and solvent. The DNA accommodates the drug by changing its conformation in a novel manner that leads folding of DNA by the generation of kinks. The aminosteroid binds to DNA through the minor groove at the kink site and stabilized the drug-DNA complex. In the present study, we reported theoretical analysis of aminosteroid, dipyrandium, binding with poly d(AT) by using an amended Zimm and Bragg theory, to explain the melting behaviour and heat capacity of DNA with and without dipyrandium binding. In this study we used experimental models of Marky et al. [13]. The sharpness of transition has been examined in terms of half width and sensitivity parameter. The results suggested that a range of parameters such as transition profile, sharpness of the transition, heat capacity curve and half widths are in good agreement with the experimental measurements for binding of dipyrandium. An understanding of drug-DNA interactions at the molecular level is important in facilitating the design of new drugs. This theoretical study would represent a further step toward the goal of understanding the stability of nucleic acid interactions with drugs and thus can be applied in biomedical industries.

Key words: Aminosteroid, DNA binding, dipyrandium, heat capacity, transition profile

Correspondig author’s e-mail: ghazala_kuddus@yahoo.com

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