Interaction of DNA with cationic vesicles: A calorimetric study
Interaction of DNA with cationic vesicles: A calorimetric study
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DOI：
10.1021/jp000636c
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发表时间：
2000-08-17
影响因子：
3.3
通讯作者：
Alexandridis, P
中科院分区：
文献类型：
--
作者：
Barreleiro, PCA;Olofsson, G;Alexandridis, P
通过等温滴定量热法、差示扫描量热法（DSC）和浊度测量研究了DNA与阳离子脂质与不同量的两性离子脂质在稀溶液中混合的囊泡的相互作用。在25 ℃下研究了挤出的纯二甲基双十八烷基溴化铵（DODAB）和氯化物（DODAC）囊泡以及具有不同量的二油酰磷脂酰乙醇胺（DOPE）的混合囊泡。DNA与阳离子囊泡的相互作用是快速和吸热的。每摩尔添加的脂质的反应焓是恒定的，随着阳离子脂质和DNA之间的电荷比的变化，但随着囊泡中两性离子脂质的量的增加而降低。焓变是恒定的，直到临界电荷比rho+/-为约0.8的脂质囊泡添加到DNA和1.2的DNA添加到脂质囊泡。在50-200 nm范围内，反应焓随Br ~-被Cl ~-取代而降低，与阳离子囊泡的大小无关。用DSC研究了DOPE对DODAB在含DNA和不含DNA的水分散液中热致行为的影响。在DODAB阳离子囊泡中包含DOPE增加了双层流动性，例如，降低熔化温度Tm。烃链的状态，固体状或流体，具有显着的影响上测得的焓变化和最强烈的形成带正电荷的，富含脂质的聚集体。
The interaction of DNA with vesicles of cationic lipids mixed with varying amounts of a zwitterionic lipid in dilute solutions was studied by isothermal titration microcalorimetry, differential scanning calorimetry (DSC), and turbidity measurements. Extruded pure dimethyldioctadecylammonium bromide (DODAB) and chloride (DODAC) vesicles and mixed vesicles with various amounts of dioleoylphosphatidylethanolamine (DOPE) were investigated at 25 degrees C. The interaction of DNA with cationic vesicles is fast and endothermic. The enthalpy of reaction per mole of lipid added is constant with varying charge ratio between cationic lipid and DNA but decreases with increasing amounts of the zwitterionic lipid in the vesicle. The enthalpy change is constant up to a critical charge ratio rho+/- of about 0.8 for the addition of lipid vesicles to DNA and 1.2 for the addition of DNA to lipid vesicles. The enthalpy of reaction decreases with the replacement of Br- by Cl- ion and is independent of cationic vesicle size in the range 50-200 nm. The effect of DOPE on the thermotropic behavior of DODAB in aqueous dispersions with and without DNA was investigated using DSC. Inclusion of DOPE in the DODAB cationic vesicle increases the bilayer fluidity, e.g., decreases the melting temperature, T-m. The status of the hydrocarbon chains, solid-like or fluid, has a pronounced effect on the measured enthalpy changes and most strongly for the formation of positively charged, lipid-enriched aggregates.