The asymmetric lipid composition in plasma membranes within the inner leaflet is not typically suitable for domain formation. Thus elucidation of the likelihood of the formation or stability of a raft-like domain in the inner leaflet is necessary. Herein we investigated the phase behavior of asymmetric membranes using coarse-grained molecular dynamics simulations. The lipid leaflet comprising dioleoylphosphatidylcholine (DOPC) and cholesterol (Chol) does not typically show well-developed domains in symmetric bilayer membranes; however, it does separate into liquid ordered (L_o) and liquid disordered (L_d) phases when the opposing leaflet containing sphingomyelin (SM), DOPC, and Chol demonstrates domain formation. We determine that interdigitated acyl chains modulated the partitioning of Chol in the opposing leaflet, resulting in phase separation. Similarly, the acyl chain length of SM within the opposing leaflet affected the phase behavior of the leaflet. Our results reveal the crucial role of interdigitation in determining the phase status in asymmetric membranes.

中文翻译：

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互指在小叶间相互作用中的关键作用：分子动力学模拟的启示。

内部小叶内质膜中的不对称脂质组成通常不适合域形成。因此，有必要阐明内部小叶中筏状结构域的形成或稳定性的可能性。在这里，我们使用粗粒度的分子动力学模拟研究了不对称膜的相行为。包含二油酰基磷脂酰胆碱（DOPC）和胆固醇（Chol）的脂质小叶通常在对称双层膜中未显示发育良好的结构域。但是，它确实分为有序液体（L _o）和无序液体（L _d）当含有鞘磷脂（SM），DOPC和Chol的相对小叶显示出结构域形成时）。我们确定交叉指的酰基链调节了相对小叶中Chol的分配，从而导致了相分离。类似地，相对小叶内SM的酰基链长度影响小叶的相行为。我们的结果揭示了交叉指在确定不对称膜中的相状态中的关键作用。