Alternate fast and slow stepping of a heterodimeric kinesin molecule.
A conventional kinesin molecule travels continuously along a microtubule in discrete 8-nm steps. This processive movement is generally explained by models in which the two identical heads of a kinesin move in a 'hand-over-hand' manner. Here, we show that a single heterodimeric kinesin molecule (in which one of the two heads is mutated in a nucleotide-binding site) exhibits fast and slow (with the dwell time at least 10 times longer than that of the fast step) 8-nm steps alternately, presumably corresponding to the displacement by the wild-type and mutant heads, respectively. Our results provide the first direct evidence for models in which the roles of the two heads alternate every 8-nm step.
Kaseda
Kuniyoshi
K
Gene Function Research Center, National Institute of Advanced Industrial Science and Technology and Japan Society for the Promotion of Science, Tsukuba, Ibaraki 305-8562, Japan.
Higuchi
Hideo
H
Hirose
Keiko
K
D019281:Dimerization; D016547:Kinesins / Q000737:chemistry* / Q000502:physiology; D008870:Microtubules / Q000502:physiology*; D008958:Models, Molecular; D008968:Molecular Conformation; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000502:physiology; D009154:Mutation / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D013997:Time Factors
D020409:Molecular Motor Proteins; D016547:Kinesins