Fig. 11.

Quantifying the effect of SP on the allosteric equilibrium. (A) A free energy diagram of GroEL’s first allosteric transition: TT to TR. The diagram indicates how the presence of a TMR dimer on a ring stabilizes the T state and increases the free energy gap between the TT and TR states. Because the allosteric transition is concerted, the effect of multiple dimers is additive. (B) Mathematically, this interpretation leads us to quantitatively account for the presence of TMR as a perturbation to the allosteric equilibrium.