Issues

Cover picture: An individual myosin V, labeled with a bifunctional rhodamine probe at fixed angle, θ_P , φ_P on its lever arm (top, no. 2) and stepping on actin, is analyzed by polarized total internal reflection microscopy (bottom). Time-resolved probe orientations are initially measured in a laboratory coordinate frame (bottom) and transformed into an actin frame (top, no. 1), giving probe angles β_P , α_P . A novel analysis allowed Lewis et al. to determine θ_P , φ_P in the lever frame (top, no. 2), which is used with measured probe angles, β_P , α_P , to calculate the physiologically relevant lever orientations, β_L , α_L (top, no. 3; see article by Lewis et al., 101–120).