Issues

Cover picture: (top) In a mixture of ATP and AMP-PNP, a single molecule of the motor enzyme kinesin-1 makes alternating runs and pauses as it moves along a microtubule. Examples of long and short runs are highlighted. Smaller panels show controls with ATP alone or AMP-PNP alone. (bottom) Proposed movement mechanism showing the two separate catalytic cycles that give rise to the long and short runs. E, microtubule-bound dimeric kinesin; T, ATP; D, ADP; I, AMP-PNP; Pi, inorganic phosphate (see article by Subramanian and Gelles, 445–455).