Abstract：
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.
摘要：
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。
