Albany 2013: Book of Abstracts
June 11-15 2013
©Adenine Press (2012)
Influence of changes in DNA conformation on thermodynamic contribution during interaction of human genomic DNA and its mutant with anticancer drugs
Isothermal calorimetry (ITC) is efficient in characterizing and recognizing both high affinity and low affinity intermolecular interactions quickly and accurately. Adriamycin (ADR) and daunomycin (DNM) are two anticancer drugs whose activity is achieved mainly by intercalation with DNA. During chemotherapy normal human genomic DNA and mutated DNA from K562 leukemic cells show different thermodynamic properties and binding affinities on interaction with ADR and DNM when followed by ITC. Normal DNA shows more than one step in kinetic analysis, which could be attributed to outside binding, intercalation and reshuffling as also suggested by Chaires et al. 1985; whereas K562 DNA fits a different binding pattern with higher binding affinities (by one order or more) compared to normal DNA. Structural properties of the interaction were followed by laser Raman spectroscopy, where difference in structure was apparent from the shifts in marker B DNA Raman bands (Ling et al., 2005). A correlation of thermodynamic contribution and structural data reveal step wise changes in normal genomic DNA conformation on drug binding. The overall structural change is higher in normal DNA-DNM interaction suggesting a partial B to A transition on drug binding. Such large changes were not observed for K562 DNA-DNM interaction which showed B to A transition properties in native from itself corroborating with our earlier findings (Ghosh et al., 2012).
Ling, J. Y., Yang, Q. Z., Luo, S. S., Li, Y. & Zhang, C. K. (2005). Preliminary Study on Cordycepin-DNA Interaction by Raman Spectroscopy. Chin Chem Lett 16, 71-74.
Ghosh, D., Saha, C., Hossain, M., Dey, S. K., & Kumar, G. S. (2012). Biophysical studies of mutated K562 DNA (erythroleukemic cells) binding to adriamycin and daunomycin reveal that mutations induce structural changes influencing binding behaviour. J Biomol Struct Dyn, in press, DOI:10.1080/07391102.2012.698190.
School of Biotechnology and Biological Sciences