The formation and closure of aqueous pores in lipid bilayers is a key step in various biophysical processes. Large pores are well described by classical nucleation theory, but the free-energy landscape of small, biologically relevant pores has remained largely unexplored. The existence of small and metastable “prepores” was hypothesized decades ago from electroporation experiments, but resolving metastable prepores from theoretical models remained challenging. Using two complementary methods—atomistic simulations and self-consistent field theory of a minimal lipid model—we determine the parameters for which metastable prepores occur in lipid membranes. Both methods consistently suggest that pore metastability depends on the relative volume ratio between the lipid head group and lipid tails: lipids with a larger head-group volume fraction (or shorter saturated tails) form metastable prepores, whereas lipids with a smaller head-group volume fraction (or longer unsaturated tails) form unstable prepores.

中文翻译：

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无张力脂质双层中的亚稳态预孔

脂质双层中水孔的形成和封闭是各种生物物理过程中的关键步骤。经典的成核理论已很好地描述了大孔，但是与生物学相关的小孔的自由能态在很大程度上仍未得到开发。几十年前通过电穿孔实验假设存在小的且亚稳态的“预孔”，但是从理论模型中解析亚稳态的预孔仍然具有挑战性。使用两种互补方法-最小脂质模型的原子模拟和自洽场理论-我们确定脂质膜中出现亚稳态预孔的参数。两种方法一致地表明，孔的亚稳态取决于脂质头基团和脂质尾巴之间的相对体积比：