Self-assembled DNA–cationic-lipid complexes: Two-dimensional smectic ordering, correlations, and interactions
Self-assembled DNA–cationic-lipid complexes: Two-dimensional smectic ordering, correlations, and interactions
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自组装 DNA-阳离子-脂质复合物：二维近晶有序、相关性和相互作用
DOI：
10.1103/physreve.58.889
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发表时间：
1998
影响因子：
2.4
通讯作者：
C. Safinya
中科院分区：
文献类型：
--
作者：
T. Salditt;I. Koltover;J. Rädler;C. Safinya
我们报道了同步辐射小角X射线散射（SAXS）研究的多层，自组装结构（复合物），形成的混合DNA与阳离子脂质体。在这些复合物中，DNA被限制在带电荷的脂质双层之间，并且作为二维（2D）近晶液晶有序。研究发现，与DNA链的2D晶格耦合的3D多层近晶相液晶的幂律双层-双层相关性显着偏离近晶相的标准Caill\'e模型所描述的相关性。为了模拟DNA的有序性，在简谐近似下，从近晶哈密顿量导出了二维近晶相关函数和相应的结构因子。然后将得到的线形拟合到DNA相关峰。它被发现，对于样品的更高的$d，$短程之间的相关性，在相邻的片的DNA必须被假定来解释的数据。从最小二乘拟合，二维DNA链间压缩模量$B$提取作为一个函数的$d$和讨论中考虑不同的可能的微观相互作用负责的顺序。
We report a synchrotron small-angle x-ray scattering (SAXS) study of the mutilayered, self-assembled structure (complex) that is formed by mixing DNA with cationic liposomes. In these complexes the DNA is confined between charged lipid bilayers and orders as a two-dimensional (2D) smectic liquid crystal. The power-law bilayer-bilayer correlations of the 3D multilayer smectic liquid crystal, which are coupled to the 2D lattice of DNA chains, are found to deviate significantly from those described by the standard Caill\'e model of smectic-$A$ phases. To model the DNA ordering, the 2D smectic correlation function and the corresponding structure factor are derived from the smectic Hamiltonian in harmonic approximation. The resulting line shape is then fitted to the DNA correlation peak. It is found that for samples of higher $d,$ short-range correlations between the DNA in adjacent sheets have to be assumed to explain the data. From the least-square fitting, the 2D DNA interchain compressibility modulus $B$ is extracted as a function of $d$ and discussed in view of different possible microscopic interactions responsible for the ordering.