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Updated: Jul 21, 2025
09:38
Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy
Published on: July 1, 2021
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Myosin-5 varies its steps along the irregular F-actin track
Adam Fineberg1,2, Yasuharu Takagi3, Kavitha Thirumurugan4,5
1Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
Biorxiv : the Preprint Server for Biology
|July 28, 2023
Summary
Molecular motors like myosin-5a take variable steps along actin tracks, not uniform ones. This adaptability allows them to function in chaotic cellular environments.
Area of Science:
- Biophysics
- Cell Biology
- Biochemistry
Background:
- Molecular motors convert chemical energy into mechanical work, essential for cellular processes.
- Myosin-5a is a key motor protein, traditionally thought to move in uniform 36nm steps along actin filaments.
- Cellular environments present challenges like disorder and Brownian motion that motors must overcome.
Approach:
- Utilized high-resolution interferometric scattering (iSCAT) microscopy to precisely measure myosin-5a step sizes.
- Analyzed the structural basis of myosin-5a stepping using electron microscopy.
- Correlated actin filament's cumulative angular disorder with observed stride length variations.
Key Points:
- Myosin-5a exhibits variable step lengths, ranging from 22 to 34 actin subunits.
- Actin filament's inherent angular disorder explains the observed range of step sizes.
- Both myosin-5a and actin are soft materials capable of adapting to cellular conditions.
Conclusions:
- Challenges the long-held view of uniform stepping for myosin-5a.
- Highlights the role of track disorder in motor protein mechanics.
- Demonstrates the adaptive nature of molecular motors and their tracks for cellular function.
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