物理化学学报 >> 2014, Vol. 30 >> Issue (11): 2142-2148.doi: 10.3866/PKU.WHXB201409253

生物物理化学 上一篇    下一篇

考拉维酸对人血清白蛋白结构的影响

何文英1, 姚小军2, 华英杰1, 黄国雷1, 吴秀丽1, 李小宝3, 韩长日3, 宋小平3   

  1. 1. 海南师范大学化学化工学院, 海口 571158;
    2. 兰州大学化学化工学院, 兰州 730000;
    3. 海南师范大学, 热带药用植物化学教育部重点实验室, 海口 571158
  • 收稿日期:2014-07-01 修回日期:2014-09-25 发布日期:2014-10-30
  • 通讯作者: 宋小平 E-mail:sxp628@126.com
  • 基金资助:

    国家国际科技合作专项(2014DFA40850)和国家自然科学基金(81160391)资助项目

Effect of Kolavenic Acid on the Structure of Human Serum Albumin

HE Wen-Ying1, YAO Xiao-Jun2, HUA Ying-Jie1, HUANG Guo-Lei1, WU Xiu-Li1, LI Xiao-Bao3, HAN Chang-Ri3, SONG Xiao-Ping3   

  1. 1. College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, P. R. China;
    2. College of Chemical and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China;
    3. Key Laboratory of Tropical Medicimal Plant Chemistry of Ministry of Education, Hainan Normal University, Haikou 571158, P. R. China
  • Received:2014-07-01 Revised:2014-09-25 Published:2014-10-30
  • Contact: SONG Xiao-Ping E-mail:sxp628@126.com
  • Supported by:

    The project was supported by the International S&T Cooperation Program of China (2014DFA40850) and National Natural Science Foundation of China (81160391).

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摘要：

利用多种荧光光谱法、紫外光谱法并结合分子模拟等方法, 表征了模拟生理条件下一种植物药活性组分考拉维酸(KA)影响人血清白蛋白(HSA)的结构信息. 同步荧光及紫外光谱证实考拉维酸的存在影响了HSA的微环境; 二维及三维荧光光谱表明考拉维酸可以猝灭HSA的内源荧光, 使其构象发生变化. 荧光偏振的测定提供了考拉维酸与HSA作用后生成的配合物弛豫时间与聚集特性的信息, 揭示KA的存在使HSA的流动性和微粘度发生变化. 定量求得不同温度下(298、308 和318 K)考拉维酸与HSA作用的键合参数和热力学参数. 分子模拟表明考拉维酸键合位点于HSA分子的疏水腔内, 并与赖氨酸Lys195 和天冬氨酸Asp451 形成三个氢键, 与HSA的键合模式主要是疏水作用; 位点竞争实验证明考拉维酸在HSA亚结构域的位点Ⅱ位发生作用. 另外, 获得的相关物理化学参数从分子水平上揭示了考拉维酸与HSA相互作用的机制. 结果表明, HSA对考拉维酸有较强的结合能力, 提示人血清白蛋白对考拉维酸可起到储存和转运的作用.

关键词: 考拉维酸, 人血清白蛋白, 分子模拟, 荧光光谱, 紫外-可见吸收光谱, 相互作用

Abstract:

The effect of Kolavenic acid (KA), an active component isolated from the genus Polyalthia, on the structure of human serum albumin (HSA) was investigated by fluorescence polarization, synchronous fluorescence, three-dimensional (3D) fluorescence, and absorption spectroscopy in combination with molecular modeling techniques under physiological conditions. The synchronous and absorption fluorescence spectra confirmed that KA has an effect on the microenvironment around HSA in aqueous solution. The two-dimensional (2D) and 3D fluorescence spectra showed that KA could quench the intrinsic fluorescence of HSA and make its conformation change. Fluorescence polarization measurements provided useful information on the relaxation time and aggregation behavior of the complex formed between HSA and KA, and indicated that the presence of KA caused changes in the fluidity and microviscosity of HSA. The binding constants and thermodynamic parameters for KA-HSA systems were obtained under different temperatures (298, 308, and 318 K). Molecular docking showed that the KAmoiety bound to the hydrophobic cavity of HSA, and there were three hydrogenbonding interactions between KAand the Lys195 andAsp451 residues. Fluorescent displacement measurements confirmed that KA bound to HSA at site Ⅱ. In addition, the binding mechanism of KA and HSA was revealed by the physicochemical parameters at the molecular level. The results showed that the interaction between KA and HSA was strong, indicating that KA may be stored and transferred by serum albumin.

Key words: Kolavenic acid, Human serum albumin, Molecular modeling, Fluorescence spectroscopy, UV-visible absorption spectroscopy, Interaction