No abstract

Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet-visible (UV-Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP-HSA complex, and the binding constant was determined to be 3.196 × 10(4) L mol(-1) at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.

This investigation was undertaken to determine the interaction of diuron with human serum albumin (HSA) was studied by monitoring the spectral behavior of diuron-HSA system. The fluorescence of HSA at 340 nm excited at 230 nm was obviously quenched by diuron due to dynamic collision and the quenching constant was of the order of 10(4) L mol(-1) at 310 K. However, no fluorescence quenching was observed when excited at 280 nm. Thermodynamic investigations revealed that the combination between diuron and HSA was entropy driven by predominantly hydrophobic interactions. The binding of diuron induced the drastic reduction in α-helix conformation and the significant enhancement in β-turn conformation of HSA. In addition, both sites marker competition study and molecular modeling simulation evidenced the binding of diuron to HSA primarily took place in subdomain IIIA (Sudlow's site II).

No abstract