Final answer:
The clamp loader binds ATP to alter its conformation and load the sliding clamp onto DNA, while ATP hydrolysis is required for clamp release. Myosin functions similarly, using ATP binding and hydrolysis to facilitate muscle contraction through its interactions with actin.
Step-by-step explanation:
The question pertains to the mechanism of ATP binding and hydrolysis in the function of molecular motors and enzymes such as myosin and clamp loaders, which are essential in cell processes like muscle contraction and DNA replication. Clamp loader binds ATP before acting to change its conformation and load the sliding clamp onto DNA. However, it does not hydrolyze ATP when adopting its altered state; merely the binding of ATP is required for this conformational change.
Subsequent to the action of the clamp loader, ATP is hydrolyzed to release the clamp along with the DNA, a process that provides the energy for the release and reset of the loader for another cycle. In contrast, myosin, which is also an ATP-dependent motor protein, uses the energy from ATP hydrolysis to enter into a 'cocked' position and is then ready for interaction with actin if the binding sites are available, leading to muscle contraction movements.