Spectroscopic and molecular modeling studies on the interactions of fluoranthene with bovine hemoglobin

This study aims to investigate the interaction between fluoranthene (FLA) and Bovine hemoglobin (BHb) by ultraviolet-visible (UV-vis) absorption, fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopy and molecular docking method. The results showed that the fluorescence intensity of BHb was declined with the increase of FLA concentration. The binding procedure was spontaneous mainly driven by hydrophobic force. The number of binding sites were 0.709 (298 K), and 1.41 (310 K). The binding constants were equal to 4.68 × 10³ mol·L^-1 at 298 K and 6.17 × 10⁵ mol·L^-1 at 310 K. The binding distance between FLA and the tryptophan residue of BHb was 4.50 nm. The results of UV-vis spectra, synchronous fluorescence and CD spectra revealed that FLA could change the conformation of BHb, which might affect the physiological functions of hemoglobin. Moreover, molecular modeling results showed that the fluorescence experimental results were in agreement with the results obtained by molecular docking.