User:Prof McCarthy/machine

The biological molecule myosin reacts to ATP and ADP to alternately engage with an actin filament and change its shape in a way that exerts a force, and then disengage to reset its shape, or conformation. This acts as the molecular drive that causes muscle contraction. Similarly the biological molecule kinesin has a two sections that alternately engage and disengage with microtubules causing the molecule to move along the microtubule and transport vesicles within the cell. These molecules are increasingly considered to be nano-machines.

Researchers have used DNA to construct nano-dimensioned four-bar linkages.^[1][2]