物理化学学报 >> 2011, Vol. 27 >> Issue (01): 156-162.doi: 10.3866/PKU.WHXB20110120

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Gemini表面活性剂(12-6-12)和DNA的相互作用

王万霞, 何云飞, 尚亚卓, 刘洪来   

  1. 华东理工大学, 结构可控先进功能材料及其制备教育部重点实验室, 上海 200237
  • 收稿日期:2010-08-09 修回日期:2010-11-09 发布日期:2010-12-31
  • 通讯作者: 尚亚卓 E-mail:shangyazhuo@ecust.edu.cn
  • 基金资助:

    国家自然科学基金(20706013, 20736002), 长江学者创新团队(IRT0721), 111 引智计划(B08021)和中央高校基本科研业务费资助项目

Interaction between the Gemini Surfactant (12-6-12) and DNA

WANG Wan-Xia, HE Yun-Fei, SHANG Ya-Zhuo, LIU Hong-Lai   

  1. Key Laboratory for Advanced Materials, East China University of Science and Technology, Shanghai 200237, P. R. China
  • Received:2010-08-09 Revised:2010-11-09 Published:2010-12-31
  • Contact: SHANG Ya-Zhuo E-mail:shangyazhuo@ecust.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20706013, 20736002), Creative Team Development Project of the Ministry of Education of China (IRT0721), 111 Project of the Ministry of Education of China (B08021) and Fundamental Research Funds for the Central Universities, China.

摘要:

应用紫外光谱、荧光探针、zeta 电位、动态光散射和凝胶电泳等方法探讨了阳离子gemini 表面活性剂C12H25N+(CH3)2―(CH2)6―(CH3)2N+C12H25·2Br-(12-6-12)与DNA之间的相互作用. 研究结果表明, 与传统表面活性剂相比, 偶联表面活性剂特殊的分子结构使其与DNA的作用更强烈. DNA引导表面活性剂在其链周围形成类胶束结构, 开始形成类胶束时对应的表面活性剂临界聚集浓度(CAC)比纯表面活性剂临界胶束浓度(CMC)低两个数量级. CAC与DNA的浓度无关, 而与表面活性剂之间的疏水作用以及表面活性剂与DNA之间的静电吸引作用密切相关. Zeta 电位和凝胶电泳结果显示了DNA链所带负电荷逐渐被阳离子表面活性剂中和的过程. 借助原子力显微镜(AFM)成功观察到了松散的线团状DNA, 球状体随机地分散在DNA链上形成类似于串珠的结构、尺寸较大的球形复合物以及其由于吸附多余的表面活性剂重新带正电而被溶解得到的较小DNA/12-6-12聚集体. 圆二色(CD)光谱结果显示, 12-6-12可以诱导DNA的构象发生改变.

关键词: Gemini表面活性剂, DNA, 相互作用, 复合物

Abstract:

Interactions between DNA and the cationic gemini surfactant hexamethylene-1,3-bis(dodecydimethylammonium bromide) (12-6-12) in an aqueous solution were investigated using UV-Vis spectroscopy, zeta potential, fluorescence emission spectroscopy, dynamic light scattering, and agarose gel electrophoresis. It could be found that interactions between DNA and the cationic gemini surfactant were stronger than interactions between DNA and traditional surfactant due to the special structure of gemini surfactant. The cationic gemini surfactant can interact with DNA at very low concentrations and micellelike structures form around the DNA chains. The micelle-like structure of 12-6-12 that is induced by DNA appears at the critical aggregation concentration (CAC). The CAC is two orders of magnitude lower than the critical micelle concentration (CMC) of 12-6-12 in a DNA-free solution. The CAC is independent of DNA concentration but it is dependent on the hydrophobic interaction between surfactant molecules and the electrostatic attractive interaction between the surfactant and DNA. Zeta potential and gel electrophoresis show that the negative charges of DNA are neutralized effectively and the zeta potential of the complex changes from negative to positive values. Atomic force microscopy (AFM) images show loose structures, beadlike structures (nucleosomes), and globe structures. Circular dichroism (CD) spectra show that the secondary structure conformation of DNA changes because of its interaction with 12-6-12.

Key words: Gemini surfactant, DNA, Interaction, Complex

MSC2000: 

  • O648