Class V myosin (myosin-V) was first found as a processive motor that moves along an actin filament with large (≈36-nm) successive steps and plays an important role in cargo transport in cells. Subsequently, several other myosins have also been found to move processively. Because myosin-V has two heads with ATP- and actin-binding sites, the mechanism of successive movement has been generally explained based on the two-headed structure. However, the fundamental problem of whether the two-headed structure is essential for the successive movement has not been solved. Here, we measure motility of engineered myosin-V having only one head by optical trapping nanometry. The results show that a single one-headed myosin-V undergoes multiple successive large (≈32-nm) steps, suggesting that a novel mechanism is operating for successive myosin movement.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - Jun 29 2004
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