物理化学学报 >> 2013, Vol. 29 >> Issue (12): 2639-2646.doi: 10.3866/PKU.WHXB201310281

生物物理化学 上一篇    下一篇

牛血清白蛋白与十二烷基硫酸钠作用的机理

宁爱民, 孟磊, 赵仲麟, 郑先福, 宛新生   

  1. 河南农业大学理学院, 郑州 450002
  • 收稿日期:2013-07-15 修回日期:2013-10-28 发布日期:2013-11-28
  • 通讯作者: 宁爱民 E-mail:nam001@126.com
  • 基金资助:

    国家自然科学基金(31100067)资助项目

Mechanism of Interaction between Bovine Serum Albumin and Sodium Dodecyl Sulfate

NING Ai-Min, MENG Lei, ZHAO Zhong-Lin, ZHENG Xian-Fu, WAN Xin-Sheng   

  1. College of Science, Henan Agricultural University, Zhengzhou 450002, P. R. China
  • Received:2013-07-15 Revised:2013-10-28 Published:2013-11-28
  • Contact: NING Ai-Min E-mail:nam001@126.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (31100067).

摘要:

利用电动势法得到了牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的结合等温线. 通过四阶导数紫外光谱法和荧光光谱法研究了相互作用过程中芳香族氨基酸残基微环境极性的变化. 通过研究发现, 随着SDS浓度的逐渐增大, SDS在BSA上的平均结合数(v)逐渐增大, 色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变, 酪氨酸残基所处微环境的极性在明显增强后稍有减弱, 苯丙氨酸残基所处微环境的极性略有增强. 结果表明, 当v由0增大到14时, SDS主要结合在BSA的Trp-213附近并逐渐形成聚集体, 从而诱导BSA由结构域ⅡA 开始逐渐展开. 此后, SDS呈正协同作用的特点与BSA 结合, v急剧增大. 当v约为302 时, SDS在BSA上的结合基本达到饱和, BSA的构象趋于稳定.

关键词: 电动势, 四阶导数紫外光谱, 荧光光谱, 芳香族氨基酸残基, 微环境, 极性, 结合位点

Abstract:

The binding isotherms of the interaction between bovine serum albumin (BSA) and sodium dodecyl sulfate (SDS) were obtained using electromotive force measurements. Changes in the microenvironmental polarity of aromatic amino acid residues during the interaction were studied using fourth-derivative ultraviolet spectroscopy and fluorescence spectroscopy. The average number (v) of SDS molecules bound to BSA increased with increasing SDS concentration. The polarity of tryptophan (Trp) residues decreased gradually and then remained almost constant. The polarity of tyrosine residues increased significantly and then decreased a little. The polarity of phenylalanine residues increased very slightly. The results show that SDS molecules bind to BSA in the vicinity of Trp-213 when v gradually increases from 0 to 14. BSA unfolds from domain ⅡA, induced by SDS aggregates formed near Trp-213. The v value then increases rapidly as a result of positive cooperative binding. When the v value reaches about 302, saturation binding is achieved and the BSA conformation remains almost unchanged.

Key words: Electromotive force, Fourth-derivative ultraviolet spectroscopy, Fluorescence spectroscopy, Aromatic amino acid residue, Microenvironment, Polarity, Binding site

MSC2000: 

  • O647