Experimental Probing and Molecular Dynamics Simulation of the Molecular Recognition of DNA Duplexes by the Flavonoid Luteolin.

Luteolin (C15H10O6) is an important flavonoid found in many fruits, plants, medicinal herbs, and vegetables exhibiting many pharmacological properties. The anticancer, antitumor, antioxidant, and anti-inflammatory activities of luteolin have been reported. The pharmacological action of small molecules is dependent upon its interaction with biomacromolecules. The interactions of small molecules with DNA play a major role in the transcription and translation process. In this work, we explored the energetic profile of DNA-luteolin interaction by isothermal titration calorimetry (ITC). The effect of temperature and salt concentration on DNA binding was examined by UV-Vis method. The mode of interaction was further probed by UV melting temperature analysis and differential scanning calorimetry. An atomic level insight on the recognition of luteolin with DNA was achieved by employing molecular dynamics (MD) simulation on luteolin in complex with AT- and GC-rich DNA sequences. AMBER force field proves to be appropriate in providing an understanding on the binding mode and specificity of luteolin with duplex DNA. MD results suggest a minor groove binding of luteolin with DNA and the binding free energy obtained is in agreement with the experimental results.