The stepping motor protein as a feedback control ratchet

It is explained how going from a one headed motor protein to a stepping two headed motor protein is equivalent to going from a stochastically flashing ratchet to a feedback control ratchet. Both these ratchets have been well studied in the literature and their speeds and efficiencies are briefly reviewed. Next it is shown how a feedback control ratchet mechanism model can account for very accurate recent data obtained on kinesin. Finally, the role of internal friction in the operation of stepping motor proteins is discussed.