Lee J Y, Schick M
Department of Physics, University of Washington, Seattle, Washington, USA.
Biophys J. 2007 Jun 1;92(11):3938-48. doi: 10.1529/biophysj.106.097063. Epub 2007 Mar 9.
We extend previous work on homogeneous bilayers to calculate the barriers to fusion of planar bilayers that contain two different amphiphiles, a lamellar former and a hexagonal former, with different compositions of the two in each leaf. Self-consistent field theory is employed, and both standard and alternative pathways are explored. We first calculate these barriers as the amount of hexagonal former is increased equally in both leaves to levels appropriate to the plasma membrane of human red blood cells. We follow these barriers as the composition of hexagonal formers is then increased in the cis layer and decreased in the trans layer, again to an extent comparable to the biological system. We find that, while the fusion pathway exhibits two barriers in both the standard and alternative pathways, in both cases the magnitudes of these barriers are comparable to one another, and small, on the order of 13 k(B)T. As a consequence, one expects that once the bilayers are brought sufficiently close to one another to initiate the process, fusion should occur rapidly.
我们扩展了之前关于均匀双层膜的研究工作，以计算包含两种不同两亲分子（一种层状形成剂和一种六方形成剂）的平面双层膜的融合能垒，每层中这两种分子的组成不同。采用自洽场理论，并探索了标准途径和替代途径。我们首先计算当两层中六方形成剂的含量同等增加到适合人类红细胞质膜的水平时的这些能垒。接着，当六方形成剂在顺式层中的组成增加而在反式层中的组成减少时，我们跟踪这些能垒，其程度同样与生物系统相当。我们发现，虽然融合途径在标准途径和替代途径中都呈现出两个能垒，但在这两种情况下，这些能垒的大小彼此相当，且较小，约为13k(B)T。因此，可以预期一旦双层膜彼此足够接近以启动该过程，融合应该会迅速发生。
