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Kinesin-microtubule binding depends on both nucleotide state and loading direction
Sotaro Uemura1, Kenji Kawaguchi, Junichiro Yajima
1Department of Physics, School of Science and Engineering, and Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Summary
Kinesin motor proteins exhibit distinct binding states (weak for ADP, strong for nucleotide-free/ATP analogs) to microtubules. These states, driven by binding energy and interaction distance, are crucial for kinesin
Area of Science:
- Molecular Biology
- Biophysics
Background:
- Kinesin is a vital motor protein responsible for intracellular transport along microtubules.
- Understanding kinesin's nucleotide-dependent binding is key to elucidating its motility mechanism.
Purpose of the Study:
- To investigate the nucleotide-dependent binding modes of kinesin heads.
- To quantify the unbinding forces of kinesin under various nucleotide conditions.
Main Methods:
- Measurement of unbinding forces for kinesin dimers (homodimers and heterodimers).
- Experiments conducted under different nucleotide states (ADP, nucleotide-free, ATP analog).
Main Results:
- Kinesin heads display both weak (ADP state) and strong (nucleotide-free, ATP analog states) binding modes.
- Binding strength correlates with unbinding force, influenced by binding energy and interaction distance.
- Directional instability in binding was observed, dependent on loading direction.
Conclusions:
- Kinesin's motility relies on distinct binding energies and characteristic interaction distances.
- These factors explain the observed binding modes and directional instability in kinesin function.