Insight into the binding mechanisms of fluorinated 2-aminothiazole sulfonamide and human serum albumin: Spectroscopic and in silico approaches

Abstract

4-Fluoro-N-(thiazol-2-yl)benzenesulfonamide (3) is a novel fluorinated compound, containing various biological activities. Therefore, absorption spectroscopy, fluorescence quenching, molecular docking, and molecular simulation were employed to investigate the interaction between 3 and human serum albumin (HSA). Firstly, compound 3 meets all criteria for drug-likeness prediction. UV absorption spectra revealed the interaction of 3 with HSA altered the microenvironment of protein, as well as circular dichroism spectroscopic analysis indicated slightly conformational changes and a reduction in α-helical content. The binding parameters of the HSA–3 complex suggested that fluorescence quenching is driven by combined static and dynamic processes. Additionally, the stability of the complex is attributed to conventional hydrogen and hydrophobic bonding interactions. Furthermore, esterase-like activity indicated that the binding of 3 might disrupt HSA's bond networks, leading to structural alterations. Consequently, the strong binding constant (Ka ≈ 1.204 × 106 M–1) aligns with the predicted unbound fraction (0.28) in serum, indicating that thiazole 3 has good bioavailability in plasma and can be effectively transported to target sites, thereby exerting its pharmaceutical effects. However, careful dosage management is essential to prevent potential adverse effects. Overall, these findings highlight the potential of 3 as a therapeutic agent, emphasizing the need for further research to optimize its uses.