Penn Medicine

Yale Goldman, M.D., Ph.D.

Myosin V walks hand-over-hand: single fluorophore imagingwith 1.5-nm localization.

Yildiz A, Forkey JN, McKinney SA, Ha T, Goldman YE, Selvin PR

Science. 2003 Jun 27;300(5628):2061-5.

Myosin V is a dimeric molecular motor that moves processively on actin, with the center of mass moving approximately 37 nanometers for each adenosine triphosphate hydrolyzed. We have labeled myosin V with a single fluorophore at different positions in the light-chain domain and measured the step size with a standard deviation of <1.5 nanometers, with 0.5-second temporal resolution, and observation times of minutes. The step size alternates between 37 + 2x nm and 37 - 2x, where x is the distance along the direction of motion between the dye and the midpoint between the two heads. These results strongly support a hand-over-hand model of motility, not an inchworm model.

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Pennsylvania Muscle Institute
Perelman School of Medicine University of Pennsylvania
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