光谱法结合分子模拟法分析毛蕊花糖苷与血清白蛋白的分子作用机制

Analysis on molecular interaction mechanism of verbascoside binding with serum albumin by spectroscopy and molecular modeling method

目的研究毛蕊花糖苷(verbascoside,VER)与牛血清白蛋白(bovine serum albumin,BSA)的分子作用机制。方法生理条件下,光谱法测定VER与BSA的相互作用参数,分子模拟建立VER-BSA结合模型,分析其结合反应机制。结果构建的VER-BSA模型表明,维持VER与BSA的相互作用力主要是氢键和范德华力,兼有疏水作用力。光谱实验表明VER与BSA的相互作用为静态结合过程,结合强度较强,VER与BSA的结合距离(r)值较小,说明发生了能量转移现象。VER对BSA的结构域微区构象产生影响,使结合位域的疏水性发生改变。解析荧光相图得出VER与BSA反应构象型态的变迁为"二态"模型。热力学参数表明VER与BSA的相互作用是以氢键和范德华力为主的分子间作用。荧光偏振定量证明BSA与VER相互作用中生成了非共价复合物。结论光谱实验与计算机模拟结果一致,可为研究VER与BSA分子作用机制提供一定参考。

Objective To study the molecular mechanism of the binding reaction between verbascoside（VER） and bovine serum albumin（BSA）. Methods Under physiological conditions, the interaction parameter of drug binding with protein was determinated by spectroscopy, VER-BSA interactional model was built and the binding reaction mechanism was analyzed. Results The established VER-BSA binding model suggested that VER can strongly bind to BSA mainly by hydrogen bonds interaction and Van der Waals force, there were hydrophobic interactions, too. The results from spectroscopy indicated that static quenching exited between VER and BSA with significant strong bond. The value of binding distances（r） was low, which indicated the occurrence of energy transfer. Through fluorescent phase diagram technical analysis, the reaction conformational pattern of VER-BSA showed ＂two-state＂ model. According to the obtained thermodynamic parameters, the main interactional force between VER and BSA was hydrogen bonds interaction and Van der Waals force. The fluorescence polarization proved that VER and BSA generated a non-covalent complex. Conclusion The experiment results are agreed with the molecular modeling, which provides the helpful reference for the study on molecular reaction mechanism of VER binding with BSA.