The human body is a complex electrical network: Nerve cells shuttle signals from the brain, and pulses in the heart cause its muscle cells to expand and contract. Cells would never receive these electrical dispatches without special proteins like the one depicted above. The porelike protein forms a potassium channel, an electrical entryway into the cell that toggles open or shut depending on the outside voltage.

In this simulation, an electrical pulse (the rainbow-colored pattern on the right) sweeps toward the potassium channel; amino acid chains that make up the protein appear as colorful ribbons, while the stringy background represents the cell's fatty membrane. Biophysicist Benoit Roux of the University of Chicago recently used the world's fastest supercomputer -- Jaguar, at Oak Ridge National Laboratory in Tennessee -- to see how each of the protein's 350,000 atoms would react to such electrical pulses. Such studies could have important medical implications: Faulty electric signaling contributes to heart arrhythmias and may increase the risk of Alzheimer's disease, too.