Liu Chang, Zhong Qi, Kang Kai, Ma Rui, Song Chen
Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
Phys Chem Chem Phys. 2025 Jan 2;27(2):740-753. doi: 10.1039/d4cp01715c.
Ca ions play crucial roles in regulating many chemical and biological processes, but their impact on lipid bilayer membranes remains elusive, especially when the impacts on the two leaflets are asymmetrical. Using a recently developed multisite Ca model, we performed molecular dynamics simulations to study the impact of Ca on the properties of membranes composed of POPC and POPS and observed that both the structure and fluidity of the membranes were significantly affected. In particular, we examined the influence of asymmetrically distributed Ca on asymmetric lipid bilayers and found that imbalanced stress in the two leaflets was generated, with the negatively charged leaflet on the Ca-rich side becoming more condensed, which in turn induced membrane curvature that bent the membrane away from the Ca-rich side. We employed continuum mechanics to study the large-scale deformations of a spherical vesicle and found that the vesicle can go through vesiculation to form a multi-spherical shape in which a number of spheres are connected with infinitesimal necks, depending on the specific Ca distributions. These results provide new insights into the underlying mechanisms of many biological phenomena involving Ca-membrane interactions and may lead to new methods for manipulating the membrane curvature of vesicles in chemical, biological, and nanosystems.
钙离子在调节许多化学和生物过程中起着关键作用，但其对脂质双分子层膜的影响仍不清楚，尤其是当对两个小叶的影响不对称时。使用最近开发的多位点钙模型，我们进行了分子动力学模拟，以研究钙对由POPC和POPS组成的膜性质的影响，并观察到膜的结构和流动性都受到了显著影响。特别是，我们研究了不对称分布的钙对不对称脂质双分子层的影响，发现两个小叶中产生了不平衡应力，富含钙一侧带负电荷的小叶变得更加致密，进而诱导膜曲率，使膜向远离富含钙一侧弯曲。我们采用连续介质力学研究了球形囊泡的大规模变形，发现囊泡可以经历囊泡化形成多球形形状，其中多个球体通过极小的颈部相连，这取决于特定的钙分布。这些结果为许多涉及钙-膜相互作用的生物现象的潜在机制提供了新的见解，并可能导致在化学、生物和纳米系统中操纵囊泡膜曲率的新方法。
