Institute of Chemistry, The Fritz Haber Research Center, and The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University, Jerusalem 9190401, Israel; Department of Molecular Chemistry and Material Science, Weizmann Institute of Science, Rehovot 7610001, Israel.
Institute of Chemistry, The Fritz Haber Research Center, and The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University, Jerusalem 9190401, Israel.
J Colloid Interface Sci. 2023 Jan;629(Pt A):165-172. doi: 10.1016/j.jcis.2022.08.123. Epub 2022 Aug 22.
To cope with stress induced by high salinity and hydrostatic pressure, some marine animals accumulate small organic solutes called osmolytes. Most notable among these osmolytes are the denaturant urea, and trimethylamine N-oxide (TMAO) that is known to stabilize proteins. Although their effects on proteins and nucleic acids have been extensively studied, osmolytes are less commonly studied in the context of lipids, which are a crucial component in many cellular processes. Here we resolve the mechanism for urea's action on the forces acting between lipid membranes, in the presence and absence of TMAO. We find that unlike the way urea denatures proteins, and by contrast to TMAO, urea does not preferentially interact with net-neutral lipid membranes. Instead, urea modulates the interactions between membranes mainly by weakening the van der Waals attraction between bilayers. Interestingly, regardless of concentration, the effects of urea and TMAO appear to be additive to a large extent, so that the presence of one osmolyte hardly changes the interaction of the other with lipid. Weak non-additive effects are likely due to structural changes in the lipid membrane induced by the osmolytes. Finally, we comment on the potential role of osmolytes acting together in the modification of lipid adhesion and fusion.
为了应对高盐度和静水压力引起的应激，一些海洋动物会积累称为渗透物的小分子有机溶质。在这些渗透物中，最引人注目的是变性剂尿素和三甲基胺 N-氧化物（TMAO），它们已知可以稳定蛋白质。尽管它们对蛋白质和核酸的作用已得到广泛研究，但渗透物在脂质方面的研究较少，而脂质是许多细胞过程的关键组成部分。在这里，我们解决了尿素在存在和不存在 TMAO 的情况下对脂质膜之间作用力的作用机制。我们发现，与尿素使蛋白质变性的方式不同，与 TMAO 相反，尿素不会优先与净中性脂质膜相互作用。相反，尿素主要通过削弱双层之间的范德华吸引力来调节膜之间的相互作用。有趣的是，无论浓度如何，尿素和 TMAO 的作用在很大程度上似乎是相加的，因此一种渗透物的存在几乎不会改变另一种渗透物与脂质的相互作用。弱非加性效应可能是由于渗透物诱导的脂质膜结构发生变化。最后，我们评论了渗透物共同作用在修饰脂质粘附和融合方面的潜在作用。
