Instituto de Física, Universidade de São Paulo, São Paulo, Brazil.
Langmuir. 2012 Mar 13;28(10):4640-7. doi: 10.1021/la3001569. Epub 2012 Feb 28.
In this work, we investigated the properties of a fusogenic cationic lipid, diC14-amidine, and show that this lipid possesses per se the capacity to adopt either an interdigitated structure (below and around its transition temperature) or a lamellar structure (above the transition temperature). To provide experimental evidence of this lipid bilayer organization, phospholipids spin-labeled at different positions of the hydrocarbon chain were incorporated into the membrane and their electron spin resonance (ESR) spectra were recorded at different temperatures. For comparison, similar experiments were performed with dimyristoyl phosphatidylcholine, a zwitterionic lipid (DMPC) which adopts a bilayer organization over a broad temperature range. Lipid mixing between diC14-amidine and asolectin liposomes was more efficient below (10-15 °C) than above the transition temperature (above 25 °C). This temperature-dependent "fusogenic" activity of diC14-amidine liposomes is opposite to what has been observed so far for peptides or virus-induced fusion. Altogether, our data suggest that interdigitation is a highly fusogenic state and that interdigitation-mediated fusion occurs via an unusual temperature-dependent mechanism that remains to be deciphered.
在这项工作中，我们研究了融合阳离子脂质体二 C14-脒的性质，并表明该脂质本身具有采用交错结构（低于和高于其转变温度）或层状结构（高于转变温度）的能力。为了提供这种脂质双层组织的实验证据，将在烃链的不同位置标记为自旋的磷脂掺入膜中，并在不同温度下记录其电子自旋共振（ESR）谱。为了进行比较，用二肉豆蔻酰磷脂酰胆碱（DMPC）进行了类似的实验，DMPC 是一种在较宽温度范围内采用双层组织的两性离子脂质。二 C14-脒和大豆卵磷脂脂质体之间的脂质混合在低于（10-15°C）转变温度（高于 25°C）时比高于转变温度时更有效。与迄今为止观察到的肽或病毒诱导融合相比，二 C14-脒脂质体的这种温度依赖性“融合”活性是相反的。总的来说，我们的数据表明交错是一种高度融合的状态，交错介导的融合通过一种尚未破译的异常温度依赖性机制发生。
