Mouritsen O G, Jørgensen K
Canadian Institute of Advanced Research, Technical University of Denmark, Lyngby.
Mol Membr Biol. 1995 Jan-Mar;12(1):15-20. doi: 10.3109/09687689509038490.
The lipid-bilayer component of cell membranes is a mesoscopic system consisting typically of the order of 10(8)-10(10) interacting particles. In its capacity as an interacting many-particle system, the membrane sustains correlated dynamical modes and it may display co-operative phenomena such as static global phase separation and dynamic local heterogeneity. These phenomena, which are highly non-trivial collective consequences of the molecular interactions, cannot be understood or described in terms of the properties of individual molecules alone. The microscopic manifestation of the co-operative modes consists in the formation of micro- and nano-scale heterogeneous structures, such as lipid domains, that are dynamically maintained. The lipid domains may be seen as either lateral density fluctuations or compositional fluctuations. The macroscopic consequences of these fluctuations are anomalies in response functions, such as the specific heat and the lateral compressibility. The dynamic heterogeneity corresponds to a specific lateral organization of the molecular constituents of the membrane. On the basis of recent experimental and theoretical progress in the study of the physical properties of lipid-bilayer membranes, in particular detailed pictures derived from computer simulations on models of bilayer membranes, it is proposed that the dynamically heterogeneous membrane states, which are induced by thermal density fluctuations and lateral compositional fluctuations, are important for passive and active membrane functions such as transmembrane permeability, enzymatic activity, and the in-plane aggregation of protein subunits to functioning protein complexes. Membrane-associated functions may be manipulated by changes in the heterogeneous membrane structure that can be significantly altered in response to changes in compositional, thermodynamic and environmental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
细胞膜的脂质双层成分是一个介观系统，通常由10⁸ - 10¹⁰个相互作用的粒子组成。作为一个相互作用的多粒子系统，膜维持着相关的动力学模式，并且可能表现出合作现象，如静态全局相分离和动态局部异质性。这些现象是分子相互作用的高度复杂的集体结果，不能仅根据单个分子的性质来理解或描述。合作模式的微观表现在于形成动态维持的微米和纳米尺度的异质结构，如脂类结构域。脂类结构域可被视为横向密度波动或成分波动。这些波动的宏观结果是响应函数中的异常，如比热和横向压缩性。动态异质性对应于膜分子成分的特定横向组织。基于脂双层膜物理性质研究的最新实验和理论进展，特别是从双层膜模型的计算机模拟中获得的详细图像，有人提出，由热密度波动和横向成分波动引起的动态异质膜状态，对于被动和主动膜功能，如跨膜通透性、酶活性以及蛋白质亚基聚合成功能性蛋白质复合物的平面内聚集，是很重要的。膜相关功能可通过异质膜结构的变化来操纵，这种变化可因成分热力学和环境条件的改变而显著改变。（摘要截断于250字）
