Department of Chemistry, Indian Institute of Technology, Patna, Bihar 801106, India.
J Phys Chem B. 2022 Oct 6;126(39):7638-7650. doi: 10.1021/acs.jpcb.2c01359. Epub 2022 Sep 27.
A recent experiment has reported the lipidome remodeling of a soil-based plant-associated bacterium due to diurnal temperature variations. The key adaptation strategy is the headgroup-specific remodeling of the acyl chain. To understand the idiosyncratic adaptation at the molecular level, we simulate the model membrane of the same bacterium using the reported lipidome compositions at four different experimental temperatures. We investigate the temperature-dependent packing density and fluidity of the membrane, the constancy of which is key to the homeoviscous adaptation. The results show that complex lipidome remodeling approximately preserves membrane properties under heat and cold stress. The headgroup-specific remodeling of the acyl chain serves to fine-tune the packing density and fluidity of the membrane at different temperatures. While lipids with strongly interacting headgroups are more abundant at higher temperatures, the lipidome is more dominated by lipids with weaker interacting headgroups at lower temperatures. This adaptation alleviates lipid membrane disruption caused by heat and cold stress. This study provides a molecular picture of the homeoviscous adaptation of the realistic lipid membrane of a soil-based bacterium.
最近的一项实验报道了由于昼夜温度变化，土壤中与植物相关的细菌的脂质组重塑。关键的适应策略是酰基链的头部基团特异性重塑。为了在分子水平上理解这种特殊的适应，我们使用报告的四种不同实验温度下的脂质组组成模拟了相同细菌的模型膜。我们研究了膜的温度依赖性堆积密度和流动性，其恒定性是同源粘性适应的关键。结果表明，复杂的脂质组重塑在热和冷应激下大致保持了膜的性质。酰基链的头部基团特异性重塑有助于在不同温度下微调膜的堆积密度和流动性。虽然具有强相互作用头部基团的脂质在较高温度下更为丰富，但在较低温度下，具有较弱相互作用头部基团的脂质则更为主导。这种适应缓解了热和冷应激引起的脂质膜破坏。本研究提供了土壤细菌真实脂质膜同源粘性适应的分子图景。
