Deciphering the role of pH in the binding of Ciprofloxacin Hydrochloride to Bovine Serum Albumin
Deciphering the role of pH in the binding of Ciprofloxacin Hydrochloride to Bovine Serum Albumin
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DOI：
10.1039/c2cp00001f
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发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Mukherjee, Saptarshi
中科院分区：
文献类型：
--
作者：
Anand, Uttam;Kurup, Lisha;Mukherjee, Saptarshi
采用圆二色性（CD）、稳态、时间分辨和动态光散射（DLS）光谱方法研究了添加氟喹诺酮类药物盐酸环丙沙星（CpH）对牛血清白蛋白（BSA）结构性质的影响。利用球形蛋白BSA中色氨酸（Trp）氨基酸残基的内源荧光，研究了两种温度下pH值对荧光的影响。CD结果表明，CpH诱导BSA的一些结构变化，这已得到很好的支持，稳态，寿命和DLS数据。Trp的荧光强度随CpH浓度的增加而逐渐减弱，证明了在pH7.4和9.2时，Trp的荧光猝灭主要是动态猝灭，而在pH4.5时，Trp的荧光猝灭主要是静态猝灭。热力学参数进行了研究，以合理化的性质结合CpH的BSA，我们得出的结论是，疏水和货车德瓦尔斯力在药物-蛋白质相互作用的过程中发挥了重要作用，在三个不同的pH值。Trp的寿命被发现随着CpH浓度的升高而降低，并且寿命的百分比降低被发现是所调查的介质的pH的函数。
The effect of the added fluoroquinolone, Ciprofloxacin Hydrochloride (CpH), on structural properties of Bovine Serum Albumin (BSA) was investigated by Circular Dichroism (CD), steady-state, time-resolved and Dynamic Light Scattering (DLS) spectroscopic approaches. The intrinsic fluorescence of the Tryptophan (Trp) amino acid residue in the globular protein BSA was made use of and the effect of pH at two different temperatures was thoroughly investigated. CD results indicate that CpH induces some structural changes in BSA and this has been well-supported by steady-state, lifetime and DLS data. The fluorescence intensity of Trp gradually decreases with the rise in concentration of CpH and we have conclusively proved that at pH 7.4 and 9.2, the mechanism of fluorescence quenching is mostly dynamic in nature, whereas at pH 4.5 mainly static quenching is operational. Thermodynamic parameters have been studied to rationalize the nature of binding of CpH to BSA, and we have concluded that hydrophobic and van der Waals forces play an important role in the process of drug-protein interaction at three different pH values. The lifetime of Trp was found to decrease with the rise in CpH concentration and the percentage reduction in lifetime was found to be a function of the pH of the medium under investigation.