Fig. 1.

Coupled model for a three-particle system. A system of three particles, 1, 2, and 3, each of which can exist in two conformations: i₀ (resting state of i) and i₁ (activated state of i). Vertical double-arrowed lines indicate the intrinsic activation constants of the particles. All three particles are thermodynamically linked to each other via four state-dependent pairwise coupling factors, as described in the text. These are depicted by the horizontal and diagonal lines connecting the two particle microstates.