State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Feb;75(2):547-52. doi: 10.1016/j.saa.2009.11.014. Epub 2009 Nov 14.
The interaction between fluoroquinolones (FQs), ofloxacin and enrofloxacin, and bovine serum albumin (BSA) was investigated by fluorescence and UV-vis spectroscopy. It was demonstrated that the fluorescence quenching of BSA by FQ is a result of the formation of the FQ-BSA complex stabilized, in the main, by hydrogen bonds and van der Waals forces. The Stern-Volmer quenching constant, K(SV), and the corresponding thermodynamic parameters, DeltaH, DeltaS and DeltaG, were estimated. The distance, r, between the donor, BSA, and the acceptor, FQ, was estimated from fluorescence resonance energy transfer (FRET). The effect of FQ on the conformation of BSA was analyzed with the aid of UV-vis absorbance spectra and synchronous fluorescence spectroscopy. Spectral analysis showed that the two FQs affected the conformation of the BSA but in a different manner. Thus, with ofloxacin, the polarity around the tryptophan residues decreased and the hydrophobicity increased, while for enrofloxacin, the opposite effect was observed.
荧光光谱法和紫外-可见光谱法研究了氟喹诺酮（FQs），氧氟沙星和恩诺沙星与牛血清白蛋白（BSA）之间的相互作用。结果表明，FQs 对 BSA 的荧光猝灭是由于 FQ-BSA 复合物的形成，该复合物主要通过氢键和范德华力稳定。估算了 Stern-Volmer 猝灭常数 K(SV)和相应的热力学参数ΔH、ΔS 和ΔG。从荧光共振能量转移（FRET）估算了供体 BSA 和受体 FQ 之间的距离 r。借助紫外-可见吸收光谱和同步荧光光谱分析了 FQ 对 BSA 构象的影响。光谱分析表明，两种 FQs 均影响 BSA 的构象，但方式不同。因此，对于氧氟沙星，色氨酸残基周围的极性降低，疏水性增加，而对于恩诺沙星，则观察到相反的效果。
