Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Chemistry and Chemical Engineering of Guangxi Normal University, Guilin, People's Republic of China.
Luminescence. 2011 Jul-Aug;26(4):296-304. doi: 10.1002/bio.1227. Epub 2010 Aug 25.
Themechanism of binding of the antivirus drug, brevifolin carboxylic acid (BCA) with bovine serum albumin (BSA) was investigated by steady-state and time-resolved fluorescence, circular dichroism (CD), Fourier transform infrared (FT-IR) and Raman spectroscopy under pseudo-physiological conditions for the first time. A strong fluorescence quenching was observed and the quenching mechanism was considered as static quenching. Various binding parameters were evaluated. The quantitative analysis of CD spectral data revealed that the a-helical content of BSA increased from 48.91% (in free BSA) to 52.46% (in bound form) in the presence of BCA. Based on the Förster's theory of non-radiation energy transfer, the relation of the binding average distance r between the donor (BSA) and acceptor (BCA) and acceptor concentration was determined. The changes in association constants of BCA-BSA in the presence of the common ions are also discussed. From the CD, FT-IR, time-resolved fluorescence and Raman spectroscopic results, it is apparent that the interaction of BCA with BSA causes a conformational change in the protein, and the Trp and Tyr residues are buried in more hydrophobic surroundings. BCA mainly binds to residue Trp 212 located in domain II of BSA by hydrophobic interaction and hydrogen bond.
首次在拟生理条件下，通过稳态和时间分辨荧光、圆二色性（CD）、傅里叶变换红外（FT-IR）和拉曼光谱研究了抗病毒药物短叶苏木酚酸（BCA）与牛血清白蛋白（BSA）结合的机制。观察到强荧光猝灭，猝灭机制被认为是静态猝灭。评估了各种结合参数。CD 光谱数据的定量分析表明，在 BCA 的存在下，BSA 的α-螺旋含量从 48.91%（在游离 BSA 中）增加到 52.46%（在结合形式中）。基于福斯特非辐射能量转移理论，确定了供体（BSA）和受体（BCA）之间结合平均距离 r 与受体浓度之间的关系。还讨论了常见离子存在下 BCA-BSA 结合常数的变化。从 CD、FT-IR、时间分辨荧光和拉曼光谱结果可以明显看出，BCA 与 BSA 的相互作用导致蛋白质构象发生变化，色氨酸和酪氨酸残基埋藏在更疏水的环境中。BCA 主要通过疏水相互作用和氢键结合到 BSA 结构域 II 中的残基 Trp 212 上。
