Publication
Population-level Membrane Diversity Triggers Growth and Division of Protocells
Publisher:
American Chemical Society (ACS)
Date:
16-11-2020
DOI:
10.26434/CHEMRXIV.13238402
Abstract: To date, multiple mechanisms have been described for the growth and ision of model protocells, all of which exploit the cumulative, unidirectional movement of lipids. The aggregate that is more complex grows at the expense of the smaller or less complex aggregate. Imbalances between surface area and volume during growth can generate filamentous vesicles which are typically ided by shear forces. Here we describe another pathway for growth and ision that depends simply on differences in composition of fatty acid membranes. Growth is driven by the entropically-favored mixing of lipids between two populations. Division is the result of growth-induced curvature. Importantly, growth and ision are cyclic and bidirectional, meaning that vesicles made from one type of lipid, e.g. short-chain fatty acids, grow and ide when fed with vesicles consisting of another type of lipid, e.g. long-chain fatty acids, and vice versa. After equilibration, additional rounds of growth and ision are possible through the addition of compositionally distinct vesicles. Since prebiotic synthesis likely gave rise to mixtures of lipids, the data are consistent with the presence of growing and iding protocells on the prebiotic Earth. /