Skeletal myosin S1 consists of two functional segments, a catalytic-domain and a lever-arm. Since the crystal structure of ADP/Vi-bound S1 exhibits a strong intramolecular flexure between two segments, inter-conversion between bent and extended forms; i.e. "tilting of the lever-arm" has been accepted as the established molecular mechanism of skeletal muscle contraction. We utilized quick-freeze...

The molecular motor myosin teams up to drive muscle contraction, membrane traffic, and cell division in biological cells. Myosin function in cells emerges from the interaction of multiple motors tethered to a scaffold, with surrounding actin filaments organized into 3D networks. Despite the importance of myosin function, the influence of intermotor interactions on collective motion remains poor...

The C-terminus of myosin-S1 forms the alpha-helical lever arm which is associated with an essential and a regulatory light chain. The lever arm is believed to work as an elastic ratchet which moves during force-generation from an up into a down position. The ELC in the heart tethers the tick and thin filaments by binding with its four EF-hand domains to the myosin lever arm, while the antenna-l...

This paper introduces the design and analysis of two types of novel inherently compliant actuators. The two actuation systems are characterized by the property that the output apparent stiffness can be varied independently from the position. The two proposed actuators can regulate the stiffness through the adjustable moment arm mechanism with minimum energy consumption. In the first VSA, this b...

Extending the body with a tool could imply that characteristics of hand movements become characteristics of the movement of the effective part of the tool. Recent research suggests that such distal shifts are subject to boundary conditions. Here we propose the existence of three constraints: a strategy constraint, a constraint of movement characteristics, and a constraint of mode of control. We...