Parallel lipoplex folding pathways revealed using magnetic tweezers.
Parallel lipoplex folding pathways revealed using magnetic tweezers.
复制标题
使用磁力镊子揭示平行脂质复合物折叠途径。
DOI：
10.1021/bm301155w
复制
发表时间：
2012
影响因子：
6.2
通讯作者：
Rybenkov,ValentinV
中科院分区：
文献类型：
--
作者：
Sun,Zhiqiang;Tikhonova,ElenaB;Zgurskaya,HelenI;Rybenkov,ValentinV
脂质包被的DNA纳米颗粒（脂质复合物）是一种强大的基因递送工具，具有很好的治疗应用前景。lipoplex组装的机制仍然知之甚少。我们探讨了DNA包装的阳离子脂质DSTAP（二硬脂酰三甲基铵-丙烷）使用磁镊。DSTAP诱导的DNA凝聚以一系列的爆发形式发生，平均步长为60-80 nm。在步骤之前的停顿时间可以近似为双峰分布，这揭示了至少两个不同的冷凝途径。快速凝聚的DNA对力诱导的解凝聚更有弹性。在高盐浓度下，稳定的，快速形成的复合物的比例下降。在散装实验中观察到类似的趋势。在低盐浓度下组装的脂质复合物甚至在转移到高盐条件后也能更有效地屏蔽DNA免受荧光染料和DNA酶的影响。这些数据表明，lipoplex折叠发生通过两个平行的途径，即使在单分子水平。通过这两个途径的进展可以使用单个DNA操作在真实的时间内监测。这两种途径的相对效率可以通过外部条件来改变。
Lipid-coated DNA nanoparticles (lipoplexes) are a powerful gene delivery tool with promising therapeutic applications. The mechanism of lipoplex assembly remains poorly understood. We explored DNA packing by a cationic lipid DSTAP (distearoyl trimethylammonium-propane) using magnetic tweezers. DSTAP-induced DNA condensation occurred as a series of bursts with the mean step size of 60–80 nm. The pause time preceding the steps could be approximated as a bimodal distribution, which reveals at least two distinct condensation pathways. The rapidly condensed DNA was more resilient to force-induced decondensation. The proportion of the stable, fast-formed complexes decreased at high salt concentrations. A similar trend was observed in bulk experiments. Lipoplexes assembled at low salt concentration more efficiently shielded DNA from fluorescent dyes and DNase even after transfer to the high salt conditions. These data reveal that lipoplex folding occurs via two parallel pathways even at the single molecule level. The progress through the two pathways can be monitored in real time using single DNA manipulations. The relative efficiency of the two pathways can be varied by external conditions.