Two different single-molecule fluorescence resonance energy transfer (smFRET) sensors are developed to detect whether kinesin is bound to its microtubule track by one or two heads. It is found that at physiological concentrations of ATP, kinesin waits in-between steps in a two-headed bound state, whereas at lower ATP concentrations, a one-head bound state predominates.
- Teppei Mori
- Ronald D. Vale
- Michio Tomishige
