%0 Book Section %1 statphys23_0544 %A Lee, J.Y. %A Schick, M. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K asymmetric bilayers field fusion membrane membranes statphys23 theory topic-10 %T Fusion of bilayer membranes with leaves of different composition and of varying intermembrane separation %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=544 %X We calculate the barriers to fusion of planar bilayers which contain two different amphiphiles, a lamellae former and a hexagonal former, using self-consistent field theory. 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, the magnitudes of these barriers are comparable to one another, and small, on the order of 13 kT. As a consequence, one expects that once the bilayers are brought sufficiently close to one another to initiate the process, fusion should occur rapidly. To determine just what is sufficiently close, we calculate the barriers to fusion as a function of the distance between membranes. The bilayers are under tension. We find that the largest barrier to fusion is that to create the metastable stalk and is the smallest when the bilayers are at a distance about 20 percent greater than the thickness of a single leaf, a distance which would correspond to between two and three nanometers for typical bilayers. The rate of increase of the free energy with distance between bilayers is calculated for the metastable stalk itself and for the barrier to the creation of this stalk. We find that they are sufficiently large that external agents such as fusion peptides must be available in order to bring bilayers sufficiently close in order that they fuse.

@incollection{statphys23_0544, abstract = {We calculate the barriers to fusion of planar bilayers which contain two different amphiphiles, a lamellae former and a hexagonal former, using self-consistent field theory. 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, the magnitudes of these barriers are comparable to one another, and small, on the order of 13 kT. As a consequence, one expects that once the bilayers are brought sufficiently close to one another to initiate the process, fusion should occur rapidly. To determine just what is sufficiently close, we calculate the barriers to fusion as a function of the distance between membranes. The bilayers are under tension. We find that the largest barrier to fusion is that to create the metastable stalk and is the smallest when the bilayers are at a distance about 20 percent greater than the thickness of a single leaf, a distance which would correspond to between two and three nanometers for typical bilayers. The rate of increase of the free energy with distance between bilayers is calculated for the metastable stalk itself and for the barrier to the creation of this stalk. We find that they are sufficiently large that external agents such as fusion peptides must be available in order to bring bilayers sufficiently close in order that they fuse.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Lee, J.Y. and Schick, M.}, biburl = {https://www.bibsonomy.org/bibtex/2f328ff9af566d2b814b85828a6f17d10/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {9af648c35a362ca6b3bde3cf498c8658}, intrahash = {f328ff9af566d2b814b85828a6f17d10}, keywords = {asymmetric bilayers field fusion membrane membranes statphys23 theory topic-10}, month = {9-13 July}, timestamp = {2007-06-20T10:16:23.000+0200}, title = {Fusion of bilayer membranes with leaves of different composition and of varying intermembrane separation}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=544}, year = 2007 }