文献类型：期刊文献

英文题名：Biophysical characterization of complexation of DNA with oppositely charged Gemini surfactant 12-3-12

作者：Zhao, Xiaofang;Shang, Yazhuo[1];Hu, Jun;Liu, Honglai;Hu, Ying

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China; E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China

年份：2008

卷号：138

期号：3

起止页码：144

外文期刊名：BIOPHYSICAL CHEMISTRY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000261346400011)】；

基金：This work was supported by the National Natural Science Foundation of China (Projects No. 20706013, 20736002), Program for Changjiang Scholars and Innovative Research Team in University (No.IRT0721) and the 111 Project of Ministry of Education of China (No. B08021).

语种：英文

外文关键词：Gemini surfactant; DNA; Interaction; Surface tension; Circular dichroism

摘要：The interaction between DNA and cationic gemini surfactant trimethylene-1, 3-bis (dodecyldimethylammonium bromide) (12-3-12) has been investigated by the measurements of fluorescence, surface tension, UV spectrum and circular dichroism (CD). Micelle-like structure of 12-3-12 induced by DNA appears at critical aggregation concentration (CAC), which is much lower than critical micelle concentration (CMC) of 12-3-12 in DNA-free solution. CAC is independent of DNA concentration, but the CMC of the mixed solutions of DNA and 12-3-12(CMCmix) increases with the increasing of DNA concentration. The surface tensions of the mixed system are higher than that of the pure surfactant solution, much different from the so-called synergistic lowering of the surface tension for other polymer-surfactant systems. Phase separation occurs after the neutralization point and the precipitate redissolves with superfluous 12-3-12. Cationic surfactant 12-3-12 can exclude ethidium bromide (EB) from the DNA/EB complex, and this process does not depend on the DNA concentration but on the charge ratio of 12-3-12 to DNA. The binding constant of EB to DNA decreases sharply at the charge ratio from 0.5 to 1.0. Circular dichroism (CD) spectra show that DNA undergoes a conformational transition from native B-form to chiral Psi-phase with increasing of 12-3-12. (C) 2008 Elsevier B.V. All rights reserved.