波动对脂质双层模拟中面积压缩性的贡献。
Undulation contributions to the area compressibility in lipid bilayer simulations.
机构信息
Theoretical Biological Physics, Department of Theoretical Physics, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm, Sweden.
出版信息
Biophys J. 2009 Nov 18;97(10):2754-60. doi: 10.1016/j.bpj.2009.08.048.
It is here shown that there is a considerable system size-dependence in the area compressibility calculated from area fluctuations in lipid bilayers. This is caused by the contributions to the area fluctuations from undulations. This is also the case in experiments. At present, such a contribution, in most cases, is subtracted from the experimental values to obtain a true area compressibility. This should also be done with the simulation values. Here, this is done by extrapolating area compressibility versus system size, down to very small (zero) system size, where undulations no longer exist. The area compressibility moduli obtained from such simulations do not agree with experimental true area compressibility moduli as well as the uncorrected ones from contemporary or earlier simulations, but tend, instead, to be approximately 50% too large. As a byproduct, the bending modulus can be calculated from the slope of the compressibility modulus versus system-size. The values obtained in this way for the bending modulus are then in good agreement with experiment.
研究表明，从脂质双层的面积波动中计算出的面积压缩系数存在相当大的系统尺寸依赖性。这是由波动对面积波动的贡献引起的。在实验中也是如此。目前，在大多数情况下，从实验值中减去这种贡献，以获得真实的面积压缩系数。模拟值也应该这样做。在这里，通过将面积压缩系数与系统尺寸进行外推，直到非常小（零）的系统尺寸，此时不再存在波动，从而实现这一点。从这种模拟中获得的面积压缩系数与实验真实的面积压缩系数以及当代或更早的模拟中的未修正的系数都不一致，但往往会大大约 50%。作为副产品，可以从压缩系数与系统尺寸的关系的斜率计算出弯曲弹性模量。以这种方式获得的弯曲弹性模量值与实验结果非常吻合。
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