VESICA: computer graphics modeling of lipid vesicles.

A vesicle simulation and computer analysis program, VESICA, is described which employs spherical projections of triangularly tessellated icosahedra to produce molecular graphics models of the three-dimensional structures of lipid vesicles. The program is used to analyze the molecular architecture of small unilamellar vesicles of dipalmitoyl-phosphatidylcholine and is demonstrated as a worthwhile investigative tool for determining the factors that govern the minimum vesicle size.