2-Phenylquinoline-polyamine conjugate (QPC): Interaction with bovine serum albumin (BSA)

A novel 2-phenylquinoline-polyamine conjugate (QPC) was synthesized and characterized, its interaction with bovine serum albumin (BSA) was evaluated using UV–Vis, fluorescence and circular dichroism (CD) spectroscopy. The results showed that QPC caused a whole train of spectral variation, including enhancement of UV–vis absorption and reduction of fluorescence (FL), indicating QPC-BSA complex formed. FL results showed that the type of FL quenching was large static quenching, which was also accompanied with a process of dynamic quenching. Binding constants, thermodynamic parameters and docking results showed that the interaction between QPC and BSA was basically a Van der Waals, hydrogen bond and hydrophobic interaction. Synchronous and 3D-FL analysis revealed that QPC resulted in unapparent conformational alteration of BSA. The docking study suggested QPC was situated at the binding sites II of BSA, and 2-phenylquinoline moiety contributed to the hydrophobic interaction. The results of molecular dynamics revealed QPC altered the conformation of BSA, which showed that the inconsistency between experimental data and theoretical calculation results may be due to the instability of the compound.