Determination on the binding of thiadiazole derivative to human serum albumin: a spectroscopy and computational approach

4-[3-acetyl-5-(acetylamino)-2,3-dihydro-1,3,4-thiadiazole-2-yl]phenyl benzoate from the family of thiadiazole derivative has been newly synthesized. It has good anticancer activity as well as antibacterial and less toxic in nature, its binding characteristics are therefore of huge interest for understanding pharmacokinetic mechanism of the drug. The binding of thiadiazole derivative to human serum albumin (HSA) has been investigated by studying its quenching mechanism, binding kinetics and the molecular distance, r between the donor (HSA) and acceptor (thiadiazole derivative) was estimated according to Forster’s theory of non-radiative energy transfer. The Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) changes of temperature-dependent K_b was calculated, which explains that the reaction is spontaneous and exothermic. The microenvironment of HSA have also been studied using synchronous fluorescence spectroscopy, and the feature of thiadiazole derivative-induced structural changes of HSA have been carried using Fourier transform infrared spectroscopy and the Molecular modelling simulations explore the hydrophobic and hydrogen bonding interactions.