Motor proteins use the energy in ATP to transport organelles, rearrange elements of the cytoskeleton during cell migration, and move chromosomes during cell division. Which of the following mechanisms is sufficient to ensure the unidirectional movement of a motor protein along its substrate?
(a) A conformational change is coupled to the release of a phosphate (Pi).
(b) The substrate on which the motor moves has a conformational polarity.
(c) A conformational change is coupled to the binding of ADP.
(d) A conformational change is linked to ATP hydrolysis.
Answer: D