类异戊二烯甘油二烷基甘油四醚(GDGTs),古细菌的特征性膜脂,广泛用于生态和地球化学研究,尤其是古环境重建。甘油单烷基甘油四醚(GMGT,也称为H-GDGT),GDGT的独特变体,具有连接两个烷基链的共价键。尽管一些研究表明GMGT和高温之间存在联系,可靠性和机制尚不清楚.利用分子动力学模拟,我们阐明了GMGT与高温的连接机制。我们的发现表明,H-桥接键减少了烷基链之间的距离,导致具有较低流动性和渗透性的较厚和较致密的膜。与GDGT相比,GMGT的扩散系数降低了约35%,表明它们作为古细菌高温适应的作用。这项研究为在地球化学研究中使用古细菌GMGT提供了机械基础,并增强了将其用于古温度重建的信心。
Isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs), characteristic membrane lipids of archaea, are widely used in ecological and geochemical studies, especially for paleoenvironmental reconstruction. Glycerol monoalkyl glycerol tetraethers (
GMGTs, also known as H-GDGTs), a unique variant of GDGTs, have covalent bonds linking the two alkyl chains. Despite some studies suggesting a link between
GMGTs and high temperatures, the reliability and mechanisms remain unclear. Using molecular dynamics simulations, we elucidated the mechanism connecting
GMGTs to high temperatures. Our findings show that H-bridging linkages reduce the distance between alkyl chains, leading to thicker and denser membranes with lower fluidity and permeability. The diffusion coefficient of
GMGTs decreased by approximately 35 % compared to GDGTs, indicating their role as a archaeal high-temperature adaptation. This study provides a mechanistic basis for using archaeal
GMGTs in geochemical studies and enhances confidence in their use for paleotemperature reconstruction.