Line tension of branching junctions of bilayer membranes

Branching of bilayer membranes appear in the inverted hexagonal phase as well as in metastable states of the lamellar phase such as membrane fusion intermediates. A method for estimating the line tension of the branching junction is proposed for molecular simulations. The line tension is calculated from the pressure tensor of equiangularly branched membranes. The simulation results agree very well with the theoretical prediction of Hamm and Kozlov's tilt model. The transition between the lamellar and inverted hexagonal phases is also investigated using the tilt model.