Institute of Theoretical Physics, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany.
J Chem Phys. 2011 Feb 7;134(5):055106. doi: 10.1063/1.3530587.
We show that lateral fluidity in membranes containing quenched protein obstacles belongs to the universality class of the two-dimensional random-field Ising model. The main feature of this class is the absence of a phase transition: there is no critical point and macroscopic domain formation does not occur. Instead there is only one phase. This phase is highly heterogeneous with a structure consisting of microdomains. The presence of quenched protein obstacles thus provides a mechanism to stabilize lipid rafts in equilibrium. Crucial for two-dimensional random-field Ising universality is that the obstacles are randomly distributed and have a preferred affinity to one of the lipid species. When these conditions are not met standard Ising or diluted Ising universality applies. In these cases a critical point does exist which then marks the onset toward macroscopic demixing.
我们表明，含有淬火蛋白障碍物的膜中的侧向流动性属于二维随机场伊辛模型的普遍性类别。该类的主要特征是没有相变：没有临界点，也不会发生宏观畴形成。相反，只有一个相。这个相具有高度的不均匀性，结构由微畴组成。因此，淬火蛋白障碍物的存在为平衡中的脂质筏提供了稳定的机制。对于二维随机场伊辛普遍性来说，至关重要的是障碍物是随机分布的，并且对一种脂质物质具有优先亲和力。当这些条件不满足时，标准伊辛或稀释伊辛普遍性适用。在这些情况下，确实存在临界点，然后标志着向宏观分相的开始。
