LoRicco Josephine G, Salvador-Castell Marta, Demé Bruno, Peters Judith, Oger Philippe M
Univ Lyon, INSA de Lyon, CNRS, MAP UMR 5240, Villeurbanne, France.
Department of Large Scale Structures, Institut Laue-Langevin, Grenoble, France.
Front Chem. 2020 Nov 12;8:594039. doi: 10.3389/fchem.2020.594039. eCollection 2020.
Archaea are known to inhabit some of the most extreme environments on Earth. The ability of archaea possessing membrane bilayers to adapt to high temperature (>85°C) and high pressure (>1,000 bar) environments is proposed to be due to the presence of apolar polyisoprenoids at the midplane of the bilayer. In this work, we study the response of this novel membrane architecture to both high temperature and high hydrostatic pressure using neutron diffraction. A mixture of two diether, phytanyl chain lipids (DoPhPC and DoPhPE) and squalane was used to model this novel architecture. Diffraction data indicate that at high temperatures a stable coexistence of fluid lamellar phases exists within the membrane and that stable coexistence of these phases is also possible at high pressure. Increasing the amount of squalane in the membrane regulates the phase separation with respect to both temperature and pressure, and also leads to an increase in the lamellar repeat spacing. The ability of squalane to regulate the ultrastructure of an archaea-like membrane at high pressure and temperature supports the hypothesis that archaea can use apolar lipids as an adaptive mechanism to extreme conditions.
已知古菌栖息于地球上一些最极端的环境中。具有膜双层的古菌适应高温（>85°C）和高压（>1000巴）环境的能力被认为是由于在双层膜的中间平面存在非极性聚异戊二烯类化合物。在这项工作中，我们使用中子衍射研究了这种新型膜结构对高温和高静水压力的响应。使用两种二醚、植烷链脂质（DoPhPC和DoPhPE）和角鲨烷的混合物来模拟这种新型结构。衍射数据表明，在高温下膜内存在流体层状相的稳定共存，并且在高压下这些相也可能稳定共存。增加膜中角鲨烷的含量可调节温度和压力方面的相分离，还会导致层状重复间距增加。角鲨烷在高压和高温下调节类古菌膜超微结构的能力支持了古菌可以使用非极性脂质作为极端条件下适应机制的假设。
