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Updated: Mar 16, 2026

Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy
Published on: July 1, 2021
Lever arm extension of myosin VI is unnecessary for the adjacent binding state
Keigo Ikezaki1, Tomotaka Komori2, Yoshiyuki Arai3
1Graduate School of Frontier Biosciences, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan; Quantitative Biology Center (QBiC), RIKEN, Furuedai, Suita, Osaka 565-0874, Japan.
Abstract:
Myosin VI is a processive myosin that has a unique stepping motion, which includes three kinds of steps: a large forward step, a small forward step and a backward step. Recently, we proposed the parallel lever arms model to explain the adjacent binding state, which is necessary for the unique motion. In this model, both lever arms are directed the same direction. However, experimental evidence has not refuted the possibility that the adjacent binding state emerges from myosin VI folding its lever arm extension (LAE). To clarify this issue, we constructed a myosin VI/V chimera that replaces the myosin VI LAE with the IQ3-6 domains of the myosin V lever arm, which cannot fold, and performed single molecule imaging. Our chimera showed the same stepping patterns as myosin VI, indicating the LAE is not responsible for the adjacent binding state.
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