In Vitro Study of Ethyl-4-(3,4.5-trimethoxyphenyl)-2,7,7- trimethyl-5-oxo1,4,5,6,7,8-hexahydroquinoline-3-carboxylate and Bovine Serum Albumin Using Multi-Spectroscopic Techniques and Molecular Docking

摘要

The binding of quinolone derivative ethyl-4-(3,4.5-trimethoxyphenyl)-2,7,7- trimethyl-5-oxo1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (ETMTMHQC) to bovine serum albumin (BSA) is investigated by various spectroscopic methods and molecular docking analysis. The fluorescence quenching spectroscopic results show that ETMTMHQC bind to the protein BSA. The binding constant value is found to be 5.2 × 10~(-6) K (mol dm~3). The thermodynamic parameter of the system shows increase in temperature with gradual decrease in Stern–Volmer quenching constant thereby indicating static quenching mode. Negative entropy and positive enthalpy indicate the hydrogen bonding interaction. The (r) distance between BSA and ETMTMHQC obtained from fluorescence resonance energy transfer is found to be 7.0 nm. The UV–visible spectra reveal the increase in absorbance on formation of BSA–ETMTMHQC complex. The CD spectral study indicates reduction of ??-helical structure in BSA and small changes in the tertiary structure of the protein. ETMTMHQC interacts strongly with BSA, and small changes in protein morphology are advised by molecular docking results. Moreover, docking results show that ETMTMHQC binds to BSA at ASN390 residue.