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Published on: February 2, 2022
Two-state displacement by the kinesin-14 Ncd stalk
Mark A Hallen1, Zhang-Yi Liang, Sharyn A Endow
1Department of Cell Biology, Structural Biology & Biophysics Program, Duke University Medical Center, Durham, NC 27710, USA. mark.hallen@duke.edu
Biophysical Chemistry
|February 4, 2011
Summary
The kinesin-14 Ncd motor
Area of Science:
- Molecular Biology
- Biophysics
Background:
- Kinesin motors are essential for intracellular transport.
- Kinesin-14 Ncd motor protein plays a role in microtubule dynamics.
- The coiled-coil stalk's rotation is hypothesized to drive Ncd's movement.
Purpose of the Study:
- To investigate the role of stalk rotation in Ncd motor function.
- To determine the conformational changes of the Ncd motor during ATP hydrolysis and microtubule binding.
Main Methods:
- Förster resonance energy transfer (FRET) assays were employed.
- Measurements were taken with wild-type Ncd motor in the presence and absence of nucleotides.
- Structural data from crystal structures and cryo-electron microscopy were utilized for comparison.
Main Results:
- The Ncd motor's stalk is ~9nm from microtubules without nucleotide, indicating an unrotated state.
- Upon binding an ATP analogue, the stalk moves within ~6nm of the microtubule surface, consistent with a rotated state.
- These findings correlate stalk rotation with specific nucleotide-binding states.
Conclusions:
- Stalk rotation is a key conformational change in Ncd motor function.
- ADP release upon microtubule binding initiates stalk rotation.
- ATP binding completes the stalk rotation, driving motor displacement along microtubules.
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