Flatness and intrinsic curvature of linked-ring membranes.
Flatness and intrinsic curvature of linked-ring membranes.
复制标题
联环膜的平坦度和固有曲率。
作者：
J. Polson;E. J. Garcia;Alexander R. Klotz
最近的实验已经阐明了着丝体的物理性质，它是在锥虫寄生虫的线粒体中发现的链甲状结构，由链状DNA环形成。受这些研究的启发，我们使用蒙特卡罗模拟来检查连接环的二维网络（“膜”）的行为。为简单起见，我们只考虑具有规则连接结构的圆形刚性网络的相同环。我们发现形状张量的特征值随膜尺寸的缩放与在自回避共价膜中观察到的平相行为一致。增加环的厚度会使膜膨胀。值得注意的是，与共价膜不同，连接环膜倾向于形成凹结构，具有与局部排除体积相互作用相关的熵源固有曲率。凹度随环厚的增加而增加，也受连接网络类型的影响。讨论了连接环模型膜的性质与在动质体中观察到的性质的相关性。
Recent experiments have elucidated the physical properties of kinetoplasts, which are chain-mail-like structures found in the mitochondria of trypanosome parasites formed from catenated DNA rings. Inspired by these studies, we use Monte Carlo simulations to examine the behavior of two-dimensional networks ("membranes") of linked rings. For simplicity, we consider only identical rings that are circular and rigid and that form networks with a regular linking structure. We find that the scaling of the eigenvalues of the shape tensor with membrane size are consistent with the behavior of the flat phase observed in self-avoiding covalent membranes. Increasing ring thickness tends to swell the membrane. Remarkably, unlike covalent membranes, the linked-ring membranes tend to form concave structures with an intrinsic curvature of entropic origin associated with local excluded-volume interactions. The degree of concavity increases with increasing ring thickness and is also affected by the type of linking network. The relevance of the properties of linked-ring model membranes to those observed in kinetoplasts is discussed.