Kinesin: A molecular motor with a spring in its step

Neil Thomas, Yasuhiro Imafuku, Tsutomu Kamiya, Katsuhisa Tawada

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


A key step in the processive motion of two-headed kinesin along a microtubule is the 'docking' of the neck linker that joins each kinesin head to the motor's dimerized coiled-coil neck. This process is similar to the folding of a protein β-hairpin, which starts in a highly mobile unfolded state that has significant entropic elasticity and finishes in a more rigid folded state. We therefore suggest that neck-linker docking is mechanically equivalent to the thermally activated shortening of a spring that has been stretched by an applied load. This critical tension-dependent step utilizes Brownian motion and it immediately follows the binding of ATP, the hydrolysis of which provides the free energy that drives the kinesin cycle. A simple three-state model incorporating neck-linker docking can account quantitatively for both the kinesin force-velocity relation and the unusual tension-dependence of its Michaelis constant. However, we find that the observed randomness of the kinesin motor requires a more detailed four-state model. Monte Carlo simulations of single-molecule stepping with this model illustrate the possibility of sub-8 nm steps, the size of which is predicted to vary linearly with the applied load.

Original languageEnglish
Pages (from-to)2363-2371
Number of pages9
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1507
Publication statusPublished - Nov 22 2002

All Science Journal Classification (ASJC) codes

  • General Agricultural and Biological Sciences
  • General Environmental Science
  • General Immunology and Microbiology
  • General Biochemistry,Genetics and Molecular Biology


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