Study on behavior intermolecular force and binding mechanism interaction between bovine hemoglobin and cyanocobalamin by using of spectroscopic and molecular docking methods.

In this study, fluorescence, synchronous fluorescence, fluorescence resonance energy transfer (FRET), Fourier transform infrared (FT-IR) and molecular docking methods were employed to investigate the binding mechanism between bovine hemoglobin (BHb) and vitamin B12 (cyanocobalamin). Since BHb shares 90% sequence similarity with human hemoglobin investigating its interactions with small molecules is highly relevant. Fluorescence data analysis under varying temperatures indicated that the complex formation between vitamin B12 and BHb is stationary with ground-state complex formation. Thermodynamic investigation indicated hydrogen bonding and hydrophobic interactions in negative changes in enthalpy and entropy during the process of binding. Förster resonance energy transfer analysis determined the binding distance of vitamin B12 with BHb tryptophan residues as 3.11 nm. FT-IR spectroscopy, synchronous fluorescence and UV-visible examinations revealed that vitamin B12 may induce structural modification in BHb. Additionally, molecular docking simulations provided information about binding interactions and validated the spectroscopic findings.