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Updated: Dec 9, 2025
Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy
Published on: July 1, 2021
Video imaging of walking myosin V by high-speed atomic force microscopy
Noriyuki Kodera1, Daisuke Yamamoto, Ryoki Ishikawa
1Department of Physics, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Abstract:
The dynamic behaviour of myosin V molecules translocating along actin filaments has been mainly studied by optical microscopy. The processive hand-over-hand movement coupled with hydrolysis of adenosine triphosphate was thereby demonstrated. However, the protein molecules themselves are invisible in the observations and have therefore been visualized by electron microscopy in the stationary states. The concomitant assessment of structure and dynamics has been unfeasible, a situation prevailing throughout biological research. Here we directly visualize myosin V molecules walking along actin tracks, using high-speed atomic force microscopy. The high-resolution movies not only provide corroborative 'visual evidence' for previously speculated or demonstrated molecular behaviours, including lever-arm swing, but also reveal more detailed behaviours of the molecules, leading to a comprehensive understanding of the motor mechanism. Our direct and dynamic high-resolution visualization is a powerful new approach to studying the structure and dynamics of biomolecules in action.
Insights
High-speed atomic force microscopy directly visualizes myosin V molecules moving along actin filaments. This breakthrough reveals detailed molecular behaviors and provides a powerful new method for studying biomolecular dynamics.
Area of Science:
- Molecular Biology
- Biophysics
- Cell Biology
Background:
- Myosin V's dynamic behavior on actin filaments was previously inferred using optical and electron microscopy.
- These techniques limited simultaneous observation of molecular structure and dynamics.
- Direct visualization of myosin V's movement and its associated structural changes remained a challenge.
Purpose of the Study:
- To directly visualize the dynamic behavior of myosin V molecules during translocation along actin filaments.
- To overcome the limitations of previous microscopy techniques in assessing structure and dynamics concurrently.
- To provide a comprehensive understanding of the myosin V motor mechanism through high-resolution dynamic imaging.
Main Methods:
- Utilized high-speed atomic force microscopy (HS-AFM) for direct visualization.
- Recorded high-resolution movies of myosin V molecules interacting with actin tracks.
- Analyzed dynamic behaviors such as lever-arm swing and other molecular movements.
Main Results:
- Directly visualized myosin V molecules in motion along actin filaments.
- Provided visual evidence for previously proposed molecular behaviors, including lever-arm swing.
- Revealed previously unobserved detailed molecular behaviors, enhancing understanding of the motor mechanism.
Conclusions:
- High-speed atomic force microscopy offers a powerful new approach for studying biomolecular structure and dynamics in action.
- Direct dynamic visualization provides unprecedented insights into molecular motor mechanisms.
- This technique bridges the gap between static structural information and dynamic functional processes.
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