Wang Anna, Szostak Jack W
School of Chemistry, UNSW Sydney, NSW 2052, Australia.
Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, U.S.A.
Emerg Top Life Sci. 2019 Nov 11;3(5):537-542. doi: 10.1042/ETLS20190021.
Primitive life must have possessed the essential features of modern cellular life, but without highly evolved proteins to perform dynamic functions such as nutrient transport and membrane remodeling. Here, we consider the membrane properties of protocells - minimal cells with hereditary material, capable of growth and division - and how these properties place restrictions on the components of the membrane. For example, the lipids of modern membranes are diacyl amphiphilic molecules containing well-over 20 carbons in total. Without proteins, these membranes are very stable and kinetically trapped. This inertness, combined with the need for enzymes to synthesize them, makes modern diacyl amphiphiles unsuitable candidates for the earliest membranes on Earth. We, therefore, discuss the progress made thus far with single-chained amphiphiles, including fatty acids and mixtures of fatty acids with related molecules, and the membrane-related research that must be undertaken to gain more insight into the origins of cellular life.
原始生命一定具备了现代细胞生命的基本特征，但没有高度进化的蛋白质来执行诸如营养物质运输和膜重塑等动态功能。在这里，我们考虑原始细胞（具有遗传物质、能够生长和分裂的最小细胞）的膜特性，以及这些特性如何对膜的组成成分产生限制。例如，现代膜的脂质是二酰基两亲分子，总共含有超过20个碳原子。没有蛋白质时，这些膜非常稳定且在动力学上处于被困状态。这种惰性，再加上合成它们需要酶，使得现代二酰基两亲分子不太可能是地球上最早的膜的候选物质。因此，我们讨论了到目前为止在单链两亲分子方面取得的进展，包括脂肪酸以及脂肪酸与相关分子的混合物，以及为了更深入了解细胞生命起源而必须开展的与膜相关的研究。
