Fig. 4: Gears of an autonomous chemically driven molecular motor.
From: Gears in chemical reaction networks for optimizing energy transduction efficiency
a Chemical reaction network (CRN) representing the motor ([2]-catenane)8 and its six conformational states. A clockwise cyclic sequence of these states corresponds to a clockwise rotation of the motor’s components (rings) relative to one another. Chemostated fuel (F) and waste (W) species drive this clockwise rotation and produce work against an external load (dashed arrows). c Schematic representation of the 20 gears ψ (external elementary flux modes) of the CRN, each corresponding to a distinct closed path of the network. Among these, only ψk, ψl, ψm, ψn, and ψs can transduce fuel-to-waste conversion into work in the clockwise direction. b Upper bound on the transduction efficiency η (solid line) as a function of operating conditions. The dotted lines represent the gear efficiencies in reverse transduction—when the load drives fuel regeneration—in regions where the corresponding gears are not thermodynamically viable in the forward direction.
