Protein lateral movement in lipid bilayers. Monte Carlo simulation studies of its dependence upon attractive protein-protein interactions
Protein lateral movement in lipid bilayers. Monte Carlo simulation studies of its dependence upon attractive protein-protein interactions
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脂质双层中的蛋白质横向运动。
DOI：
10.1016/0005-2736(86)90381-0
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
D. Chisholm
中科院分区：
文献类型：
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作者：
D. Pink;D. Laidlaw;D. Chisholm
我们研究了三角形晶格上六边形的随机运动，其中阻碍扩散的唯一机制是（i）六边形之间的硬核排斥，阻塞路径和（ii）六边形对之间的吸引力相互作用，可以引起六边形聚集。这是早期工作的延伸（Pink，DA（1985）Biochim. Biophys. Acta 818，200-204），其研究了晶格上六边形的扩散如何仅受（i）的影响。该系统是一个简单的模型的运动的整体蛋白质，在平面的脂双层，随机力的影响下。相反的情况下，（ii）是不存在的，我们发现，有两种行为所确定的临界吸引相互作用能，Kv（c）小于0，这取决于六边形浓度，c，（即后脂质：蛋白质的比例）。对于吸引相互作用能，K v，位于0和K v（c）之间，扩散系数D基本上是恒定的，而如果K v小于K v（c），则D随着K v的减小而减小。在该地区的D迅速变化与K v，长寿命的动态集群，这是聚集的形式，出现。我们的结论是，在对比硬核排斥之间的六边形，可以减少D高达约一个数量级取决于六边形浓度，有吸引力的，集群诱导，相互作用可以减少D的许多数量级。我们已经将我们的结果与30° C下DMPC双层中细菌视紫红质的横向扩散的测量相关联，并且预测当脂质：蛋白质比率福尔斯下降到100以下时，具有1至10 ms的寿命的动态蛋白质簇或聚集体应该变得明显。随着比率变小，团簇的寿命应该增加。
We have studied the random movement of hexagons on a triangular lattice where the only mechanisms hindering diffusion are (i) the hard-core repulsion between hexagons which block pathways and (ii) attractive interactions between pairs of hexagons which can give rise to hexagon aggregation. This is an extension of earlier work (Pink, DA (1985) Biochim. Biophys. Acta 818, 200–204) which studied how diffusion of hexagons on a lattice was affected only by (i). This system is a simple model of the movement of integral proteins, in the plane of a lipid bilayer, under the influence of random forces. In contrast to the case where (ii) was absent, we find that there are two kinds of behaviour determined by a critical attractive interaction energy, K v∗(c) less than 0 which depends upon the hexagon concentration, c,(ie upon lipid: protein ratio). For attractive interaction energies, K v, lying between 0 and K v∗(c), the diffusion coefficient D is essentially constant, whereas if K v is less than K v∗(c) then D decreases by orders of magnitude as K v decreases. In the region where D changes rapidly with K v, long-lived dynamical clusters, which is the form that the aggregation takes, appear. We conclude that, in contrast to hard-core repulsions between hexagons which can decrease D by up to about one order of magnitude depending upon the hexagon concentration, the attractive, cluster-inducing, interaction can decrease D by many orders of magnitude. We have related our results to measurements of the lateral diffusion of bacteriorhodopsin in DMPC bilayers at 30° C and predict that dynamical protein clusters or aggregates with lifetimes ranging from 1 to 10 ms should become apparent when the lipid: protein ratio falls below 100. As the ratio becomes smaller, the lifetimes of the clusters should increase.