DNA Condensation Induced by a Star-Shaped Hexameric Cationic Surfactant
DNA Condensation Induced by a Star-Shaped Hexameric Cationic Surfactant
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星形六聚阳离子表面活性剂诱导的 DNA 缩合
DOI：
10.1021/acsami.7b04317
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发表时间：
2017-07-19
影响因子：
9.5
通讯作者：
Wang, Yilin
中科院分区：
文献类型：
--
作者：
Fan, Yaxun;Wang, Hua;Wang, Yilin
采用c电位、动态光散射、原子力显微镜、等温滴定量热法、溴化乙锭排阻法、圆二色谱法和细胞毒性试验研究了星形六聚季铵盐表面活性剂PAHB与小牛胸腺DNA的相互作用及其诱导的DNA缩合.随着PAHB的加入，长链DNA分子表现出连续的构象转变，从伸长的卷曲到部分凝聚的簇状聚集体，到一个球串结构，然后到一个完全凝聚的小球，直到PAHB和DNA之间的相互作用的饱和点，这是略高于它们的电荷中和点。PAHB的多个正电荷头基与DNA的多个负电荷磷酸基团之间的强吸引静电相互作用以及PAHB的多个烷基链之间的疏水相互作用是产生有效缩合的主要原因。此外，PAHB分子构象从星形向爪形和锯齿形的转变也影响DNA构象的转变。PAHB虽然显著改变了DNA的构象，但DNA的二级结构没有发生明显的变化，当DNA部分缩合时，PAHB/DNA混合物没有表现出细胞毒性。这些结果表明，星形寡聚阳离子表面活性剂是一种潜在的基因转染凝聚剂。
The interactions between a star-shaped hexameric cationic quaternary ammonium surfactant PAHB and calf thymus DNA and induced DNA condensation were investigated by c-potential, dynamic light scattering, atomic force microscopy, isothermal titration calorimetry, ethidium bromide exclusion assay, circular dichroism, and cytotoxicity assay. With the addition of PAHB, long extended DNA molecules exhibit successive conformational transitions from elongated coil to a partially condensed cluster-like aggregate, to a globules-on-a-string structure, and then to a fully condensed globule until the saturation point of interaction between PAHB and DNA, which is slightly above their charge neutralization point. The efficient condensation is mainly produced by the strong attractive electrostatic interaction between the multiple positively charged headgroups of PAHB and negatively charged phosphate groups of DNA, and the hydrophobic interaction among the multiple alkyl chains of PAHB. Moreover the transition of the DNA conformation is also affected by the transitions of PAHB molecular conformation from star-shaped to claw-like and pyramid-like. Although the DNA conformation is significantly changed by PAHB, the DNA secondary structure does not display obvious variations, and the PAHB/DNA mixture does not show cytotoxicity when DNA is partially condensed. These results indicate that star-shaped oligomeric cationic surfactant is a potential condensing agent for gene transfection.