Download MendeleyStructural basis for stabilization of human telomeric G-quadruplex [d-(TTAGGGT)] 4 by anticancer drug epirubicin.
Barthwal, R., Raje, S., Pandav, K.(2020) Bioorg Med Chem 28: 115761-115761
- PubMed: 32992248
- DOI: https://doi.org/10.1016/j.bmc.2020.115761
- Primary Citation of Related Structures:
6KXZ - PubMed Abstract:
Anthracycline anticancer drugs show multiple strategies of action on gene functioning by regulation of telomerase enzyme by apoptotic factors, e.g. ceramide level, p53 activity, bcl-2 protein levels, besides inhibiting DNA/RNA synthesis and topoisomerase-II action. We report binding of epirubicin with G-quadruplex (G4) DNA, [d-(TTAGGGT)] 4 , comprising human telomeric DNA sequence TTAGGG, using 1 H and 31 P NMR spectroscopy. Diffusion ordered spectroscopy, sequence selective changes in chemical shift (~0.33 ppm) and line broadening in DNA signals suggest formation of a well-defined complex. Presence of sequential nuclear Overhauser enhancements at all base quartet steps and absence of large downfield shifts in 31 P resonances preclude intercalative mode of interaction. Restrained molecular dynamics simulations using AMBER force field incorporating intermolecular drug to DNA interproton distances, involving ring D protons of epirubicin depict external binding close to T1-T2-A3 and G6pT7 sites. Binding induced thermal stabilization of G4 DNA (~36 °C), obtained from imino protons and differential scanning calorimetry, is likely to come in the way of telomerase association with telomeres. The findings pave the way for drug-designing with modifications at ring D and daunosamine sugar.
Organizational Affiliation:
Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India. Electronic address: ritu.barthwal@bt.iitr.ac.in.
