What will car motors look like in a million years? It's hard to tell, but biological cells seem to have found an ideal engine that they use since the early days of evolution. A spoonful of their engines generates about as much total torque as the strongest car engine today. The engine is called FoF1-ATP synthase and synthesizes the molecule ATP by combining two generator-like motors, Fo-ATPase and F1-ATPase, coupled through a single axle, one motor (Fo) that converts the cell's electrical energy into rotation, another one (F1) that converts rotation into chemical synthesis (see November 2003 highlight). ATP synthase, found throughout the whole kingdom of life, can also work in reverse, turning ATP into electrical energy. Cells typically use the energy of sun light or of food to generate an electrical potential by pumping protons that carry a positive charge across their cell membrane. The energy stored drives the protons back through Fo-ATPase enforcing rotation of the axle; the rotation in turn induces ATP synthesis in F1-ATPase. In one of the largest computational and mathematical biomodeling projects undertaken to this day and reported recently, researchers build from available disjoint structural data a model of Fo-ATPase and demonstrated its function as a motor turning proton conduction into rotation of a cylindrical protein complex. By linking nanosecond molecular modeling to a mathematical model of the motor's key elements, they could follow Fo-ATPase function properly, even when the load arising from driving synthesis in F1-ATPase was added. FoF1-ATP synthase being one of the largest molecular machines in biological cells, modelers needed to employ for its study the most advanced tools, NAMD and massively parallel computers, along with a new approach that combined molecular dynamics and stochastic mathematics.