Gaussian curvature elasticity determined from global shape transformations and local stress distributions: a comparative study using the MARTINI model
Gaussian curvature elasticity determined from global shape transformations and local stress distributions: a comparative study using the MARTINI model
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DOI：
10.1039/c2fd20087b
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发表时间：
2013-01-01
影响因子：
3.4
通讯作者：
Deserno, Markus
中科院分区：
文献类型：
--
作者：
Hu, Mingyang;de Jong, Djurre H.;Deserno, Markus
我们通过应用Hu等人最近提出的方法，计算了系统粗粒度（CG）单组分脂质膜的高斯曲率模量(k) / bar。[J] ., 2012, 22(3): 1,2-二肉豆醇酰基- n-甘油-3-磷酸胆碱（DMPC）。我们发现高斯曲率模量和平均曲率模量之间的弹性比的值(k) / bar /k = -1.04 +/- 0.03，并推断单层弹性比的值(k) / bar (m)/k(m)近似为-0.98 +/- 0.09，其中后者是基于单层中性表面与双层中间层的距离z(0)和自发脂质曲率k -0m的合理假设。通过分析我们系统的横向应力剖面sigma(0)(z)，其他两种脂质类型和文献中的相关数据，我们表明，通过sigma(0)(z)的第一和第二矩确定k -0m和(k) over bar会导致这些观测值在物理上难以置信。我们之前在一个更简单的CG模型中观察到的这种差异表明，从简单连续介质假设中得出的力矩条件忽略了脂质双分子层中物理上重要的相关性的影响。
We calculate the Gaussian curvature modulus (k) over bar of a systematically coarse-grained (CG) one-component lipid membrane by applying the method recently proposed by Hu et al. [Biophys. J., 2012, 102, 1403] to the MARTINI representation of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). We find the value (k) over bar /k = -1.04 +/- 0.03 for the elastic ratio between the Gaussian and the mean curvature modulus and deduce (k) over bar (m)/k(m) approximate to -0.98 +/- 0.09 for the monolayer elastic ratio, where the latter is based on plausible assumptions for the distance z(0) of the monolayer neutral surface from the bilayer midplane and the spontaneous lipid curvature K-0m. By also analyzing the lateral stress profile sigma(0)(z) of our system, two other lipid types and pertinent data from the literature, we show that determining K-0m and (k) over bar through the first and second moment of sigma(0)(z) gives rise to physically implausible values for these observables. This discrepancy, which we previously observed for a much simpler CG model, suggests that the moment conditions derived from simple continuum assumptions miss the effect of physically important correlations in the lipid bilayer.