Univ. Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France.
Institut Laue - Langevin, 38042 Grenoble, France.
Langmuir. 2020 Nov 17;36(45):13516-13526. doi: 10.1021/acs.langmuir.0c02258. Epub 2020 Nov 4.
Origin of life scenarios generally assume an onset of cell formation in terrestrial hot springs or in the deep oceans close to hot vents, where energy was available for non-enzymatic reactions. Membranes of the protocells had therefore to withstand extreme conditions different from what is found on the Earth surface today. We present here an exhaustive study of temperature stability up to 80 °C of vesicles formed by a mixture of short-chain fatty acids and alcohols, which are plausible candidates for membranes permitting the compartmentalization of protocells. We confirm that the presence of alcohol has a strong structuring and stabilizing impact on the lamellar structures. Moreover and most importantly, at a high temperature (> 60 °C), we observe a conformational transition in the vesicles, which results from vesicular fusion. Because all the most likely environments for the origin of life involve high temperatures, our results imply the need to take into account such a transition and its effect when studying the behavior of a protomembrane model.
生命起源场景通常假设在陆地温泉或靠近热液喷口的深海中开始形成细胞，在这些地方有非酶反应所需的能量。因此，原细胞的膜必须能够承受与当今地球表面不同的极端条件。我们在这里对由短链脂肪酸和醇组成的囊泡进行了详尽的温度稳定性研究，直至 80°C，这些囊泡是允许原细胞分隔的膜的合理候选物。我们证实，醇的存在对层状结构具有强烈的结构化和稳定作用。此外，最重要的是，在高温（>60°C）下，我们观察到囊泡发生构象转变，这是囊泡融合的结果。由于生命起源的所有最可能环境都涉及高温，因此我们的结果意味着在研究原细胞膜模型的行为时，需要考虑这种转变及其影响。
