TITLE:
Biophysical Characterization of Genistein in Its Natural Carrier Human Hemoglobin Using Spectroscopic and Computational Approaches
AUTHORS:
Biswapathik Pahari, Sandipan Chakraborty, Bidisha Sengupta, Sudip Chaudhuri, William Martin, Jasmine Taylor, Jordan Henley, Donald Davis, Pradip K. Biswas, Amit K. Sharma, Pradeep K. Sengupta
KEYWORDS:
Natural Drug Carrier; Fluorescence; Circular Dichroism; Molecular Dynamics; Docking
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.4 No.8A,
July
29,
2013
ABSTRACT:
Steady state and time resolved fluorescence spectroscopy, combined with molecular dynamics simulation, have been used to explore the interactions of a therapeutically important bioflavonoid, genistein, with normal human hemoglobin (HbA). Binding constants estimated from the fluorescence studies were K = (3.5 ± 0.32) ×104M-1 for genistein. Specific interactions with HbA were confirmed from flavonoid-induced fluorescence quenching of the tryptophan in the protein HbA. The mechanism of this quenching involves both static and dynamic components as indicated by: (a) increase in the values of Stern-Volmer quenching constants with temperatures, (b) / is slightly > 1 (where and are the unquenched and quenched tryptophan fluorescence lifetimes (averaged) respectively). Molecular docking and dynamic simulations reveal that genistein binds between the subunits of HbA, ~18? away from the closest heme group of chain α1, emphasizing the fact that the drug does not interfere with oxygen binding site of HbA.