Observation of Myosin V with an attached micrometer-sized rod revealed that the leading neck swings unidirectionally forward while the trailing neck undergoes extensive Brownian rotation before landing.
The study demonstrates that Myosin V moves via a combination of active lever-action swing of the leading neck and Brownian motion of the trailing head.
Myosin V is a molecular motor that moves cargo along actin filaments. Its two heads, each attached to a long and relatively stiff neck, move alternately forward in a "hand-over-hand" fashion. To observe under a microscope how the necks move, we attached a micrometer-sized rod to one of the necks. The leading neck swings unidirectionally forward, whereas the trailing neck, once lifted, undergoes extensive Brownian rotation in all directions before landing on a site ahead of the leading head. The neck-neck joint is essentially free, and the neck motion supports a mechanism where the active swing of the leading neck biases the random motion of the lifted head to let it eventually land on a forward site.
Shiroguchi et al. (Fri,) conducted a other in Myosin V molecular motor mechanics. Attachment of a micrometer-sized rod to one of the necks was evaluated on Observation of neck movement under a microscope. Observation of Myosin V with an attached micrometer-sized rod revealed that the leading neck swings unidirectionally forward while the trailing neck undergoes extensive Brownian rotation before landing.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: