Myosin-V stepping kinetics: a molecular model for processivity

M Rief, RS Rock, AD Mehta… - Proceedings of the …, 2000 - National Acad Sciences
M Rief, RS Rock, AD Mehta, MS Mooseker, RE Cheney, JA Spudich
Proceedings of the National Academy of Sciences, 2000National Acad Sciences
Myosin-V is a molecular motor that moves processively along its actin track. We have used a
feedback-enhanced optical trap to examine the stepping kinetics of this movement. By
analyzing the distribution of time periods separating discrete≈ 36-nm mechanical steps, we
characterize the number and duration of rate-limiting biochemical transitions preceding each
such step. These data show that myosin-V is a tightly coupled motor whose cycle time is
limited by ADP release. On the basis of these results, we propose a model for myosin-V …
Myosin-V is a molecular motor that moves processively along its actin track. We have used a feedback-enhanced optical trap to examine the stepping kinetics of this movement. By analyzing the distribution of time periods separating discrete ≈36-nm mechanical steps, we characterize the number and duration of rate-limiting biochemical transitions preceding each such step. These data show that myosin-V is a tightly coupled motor whose cycle time is limited by ADP release. On the basis of these results, we propose a model for myosin-V processivity.
National Acad Sciences