荧光光谱法结合分子对接探究pH对姜黄素与牛血清白蛋白结合的影响

Study on the effect of pH on the bingding of curcumin and bovine serum albumin by fluorescence spectroscopy combined with molecular docking methods

中文关键词:  牛血清白蛋白  荧光光谱法  姜黄素  分子对接

英文关键词:bovine serum albumin  fluorescence spectroscopy  curcumin  molecular docking

中文摘要:

      目的 采用荧光光谱法结合分子对接探究姜黄素(curcumin, CUR)与牛血清白蛋白(bovine serum albumin, BSA)在不同pH条件下相互作用。方法 通过荧光光谱法计算结合常数和热力学参数分析CUR对BSA荧光猝灭作用和机制; 采用位点Marker和分子对接分析结合位点。结果 CUR与BSA结合形成了复合物, 产生内源性荧光猝灭作用, 属于静态猝灭。不同pH条件下的结合作用力不同, 但结合位点数目均为1。由同步荧光可知, 色氨酸残基附近疏水性增强, 说明与CUR结合后BSA构象出现了收缩, 结合位点靠近色氨酸。位点Marker实验证明pH影响CUR与BSA结合位点, 分子对接结果表明, pH 7.4时CUR与BSA的结合位点位于Sudlow’s site I附近。结论 本研究表明pH影响CUR与BSA的结合反应, 为CUR的活性保护及蛋白基递送载体研究提供理论支持。

英文摘要:

      Objective To investigate the interaction between curcumin (CUR) and bovine serum albumin (BSA) at different pH by fluorescence spectroscopy combined with molecular docking. Methods The binding constants and thermodynamic parameters were calculated by fluorescence spectroscopy to analyze the quenching effect and mechanism of CUR on BSA fluorescence, and the binding sites were analyzed by site marker and molecular docking. Results The compound was formed by the combination of CUR and BSA, which produced endogenous fluorescence quenching, which was static quenching. The binding force varied under different pH conditions, but the numbers of binding sites were all 1. According to synchrontron fluorescence, the hydrophobicity was enhanced in the vicinity of the tryptophan residue, indicating that BSA conformation contracted after binding to CUR and the binding site was close to the tryptophan. Site marker experiments demonstrated that pH affected the binding site of CUR to BSA, and molecular docking results indicated that the binding site of CUR to BSA wasnear Sudlow’s site I at pH 7.4. Conclusion This study shows that pH affects the binding reaction between CUR and BSA, and it is of great significance to study the activity protection and protein-based delivery vector of CUR.