Molecular motors: ratchet model.
Gianluca Lattanzi
Abstract
Molecular motors is the common name for a family of proteins which
can use the energy provided by the chemical reaction of ATP
hydrolysis to perform mechanical work. From a thermodynamic point
of view they are out of equilibrium systems for which two
generalized forces can be defined: the external load, coupled
to the velocity of the motor and the chemical potential
difference in the reaction, coupled to the rate of ATP
consumption.
A theoretical continuous two-state ratchet model for molecular
motors, based on two coupled Fokker--Planck equations, is shown
to be consistent with the Michaelis--Menten mechanism for
enzymatic catalysis. Strikingly this coarse grained model
accounts at least qualitatively for the recent experimental
observation of an increase in the Michaelis constant with
applied load. Our calculations also indicate that the observed
strong increase could be due to an approximation in the law used
to fit the data.
Elenco dei partecipanti al convegno di Bari.