Huertas M L, Cruz V, Cascales J J, Acuña A U, García de la Torre J
Departamento de Química Física, Facultad de Química, Universidad de Murcia, Spain.
Biophys J. 1996 Sep;71(3):1428-39. doi: 10.1016/S0006-3495(96)79344-X.
We propose a simple model for the distribution of position and orientation and the diffusion of a hydrophobic probe molecule embedded in a membrane. The molecule experiences both a Maier-Saupe orienting potential as well as an enclosing potential of repulsion from the membrane walls. A statistical thermodynamics treatment of the model provides predictions of the location and orientation of the molecule within the membrane. In particular, we evaluate the order parameter of the molecule in terms of the model constants. The diffusivity of the probe is studied by Brownian dynamics simulation. For rotational diffusion, we check an available analytical approximate treatment that allows for the prediction of the dynamics in terms of equilibrium quantities. We also pay attention to quantities related to the initial and mean reorientational rate of the probe. For translational diffusion, we use the simulation results to analyze some general aspects of lateral and transversal diffusion.
我们提出了一个简单的模型，用于描述嵌入膜中的疏水探针分子的位置和取向分布以及扩散情况。该分子既受到迈尔 - 绍普取向势，也受到来自膜壁的排斥性围闭势。对该模型进行统计热力学处理，可以预测分子在膜内的位置和取向。特别是，我们根据模型常数评估分子的序参量。通过布朗动力学模拟研究探针的扩散系数。对于旋转扩散，我们检验了一种可用的解析近似处理方法，该方法能够根据平衡量预测动力学。我们还关注与探针初始和平均重取向速率相关的量。对于平动扩散，我们利用模拟结果分析横向和纵向扩散的一些一般方面。
