论文标题
离子诱导的瞬态电势波动有助于孔形成和阳离子通过脂质膜的转运
Ion-induced transient potential fluctuations facilitate pore formation and cation transport through lipid membranes
论文作者
论文摘要
通过脂质膜的非辅助离子转运在许多细胞功能中起着至关重要的作用，没有生命是不可能的，但是由于其分子复杂性，该过程背后的确切机制仍然未知。在这里，我们证明了膜电位波动与二价离子转运之间的直接联系。高通量宽场第二谐波（SH）显微镜表明，膜电位波动在脂质双层系统中普遍发现。分子动力学模拟表明，膜电位的这种变化减少了瞬态孔形成的自由能成本，并增加了开放孔的离子通量。这些瞬态毛孔可以充当离子传输的导管，我们为一系列二价阳离子（Cu $^{2+} $，Ca $^{2+} $，BA $^{2+} $，mg $^{2+} $）进行图像。结合了实验和计算结果，我们表明，通过离子诱导的静电场形成的孔渗透是无辅助离子转运的可行机制。
Unassisted ion transport through lipid membranes plays a crucial role in many cell functions without which life would not be possible, yet the precise mechanism behind the process remains unknown due to its molecular complexity. Here, we demonstrate a direct link between membrane potential fluctuations and divalent ion transport. High-throughput wide-field second harmonic (SH) microscopy shows that membrane potential fluctuations are universally found in lipid bilayer systems. Molecular dynamics simulations reveal that such variations in membrane potential reduce the free energy cost of transient pore formation and increase the ion flux across an open pore. These transient pores can act as conduits for ion transport, which we SH image for a series of divalent cations (Cu$^{2+}$, Ca$^{2+}$, Ba$^{2+}$, Mg$^{2+}$) passing through GUV membranes. Combining the experimental and computational results, we show that permeation through pores formed via an ion-induced electrostatic field is a viable mechanism for unassisted ion transport.
