Water-soluble polyion complex associates of DNA and poly(ethylene glycol)-poly(L-lysine) block copolymer
Water-soluble polyion complex associates of DNA and poly(ethylene glycol)-poly(L-lysine) block copolymer
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DOI：
10.1021/bc9701306
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发表时间：
1997-09-01
影响因子：
4.7
通讯作者：
Kataoka, K
中科院分区：
文献类型：
--
作者：
Katayose, S;Kataoka, K
研究了聚（乙二醇） - 聚（L - 赖氨酸）（PEG - PLL）AB型嵌段共聚物在水介质中与鲑鱼睾丸DNA或Col E1质粒DNA的复合物形成。PEG - PLL的PLL链段通过静电力与核酸相互作用，形成直径约为50 nm的水溶性复合物。围绕聚离子复合物核心的PEG链段即使在化学计量条件下（此时PEG - PLL中L - 赖氨酸与DNA中磷酸盐的单元比例相等）也能防止复合物沉淀。热变性曲线的特征表明，与由分子量与PEG - PLL中PLL链段相同的PLL均聚物和DNA形成的复合物相比，PEG - PLL / DNA复合物中DNA结构具有更高的稳定性。这种对DNA结构的稳定作用可能是由于DNA被分隔到介电常数低的PEG微环境中。通过添加聚阴离子[聚（L - 天冬氨酸）]进一步验证了PEG - PLL / DNA复合物的可逆性质：聚（L - 天冬氨酸）取代了PEG - PLL复合物中的DNA，导致介质中游离DNA的释放。此外，PEG - PLL / DNA复合物对DNase I的攻击表现出高度的抗性，这表明通过隔离到具有PEG栅栏的复合物核心中实现了对DNA的保护。
Complex formation of poly(ethylene glycol)-poly(L-lysine) (PEG-PLL) AB type block copolymer with salmon testes DNA or Col El plasmid DNA in aqueous milieu was studied. The PLL segment of PEG-PLL interacts with nucleic acid through an electrostatic force to form a water-soluble complex associate with a diameter of ca. 50 nm. PEG segments surrounding the core of the polyion complex prevented the complex from precipitation even under stoichiometric conditions, at which the unit ratio of L-lysine in PEG-PLL and phosphate in the DNA is equal. The profile of the thermal melting curve revealed a higher stabilization of DNA structure in PEG-PLL/DNA complexes compared to that in the complex made from DNA and PLL homopolymer with the same molecular weight as the PLL segment in PEG-PLL. This stabilizing effect on the DNA structure may be due to the compartmentalization of DNA into the microenvironment of PEG with low permittivity. The reversible nature of the PEG-PLL/DNA complex was further verified through the addition of polyanion [poly(L-aspartic acid)]: Poly(L-aspartic acid) replaced DNA in the complex with PEG-PLL, resulting in the release of free DNA in the medium. Furthermore, the PEG-PLL/DNA complex showed high resistance against DNase I attack, suggesting DNA protection through the segregation into the core of the associate having PEG palisade.