Table 1.

Parameter free energies

Parameter	ΔG(kcal/mol)	±
OR1*	−12.5	0.5
OR2*	−10.5	0.5
OR3*	−9.5	0.5
OR3-r1†‡	−6.6	0.5
OR12coop*	−2.7	0.5
OR23coop*	−2.9	0.5
OL1§	−13.0	0.5
OL2§	−11.2	0.5
OL3§	−12.0	0.5
OL3–4‡	see ΔGns
OL12coop§	−2.7	0.5
OL23coop§	−2.0	0.5
Δ Goct†‡	−0.5	0.5
Δ Gtet†‡	−3.0	0.5
Δ Gns‡¶	−4.1	0.9

We varied all parameters in increments of 0.1 kcal/mol over the range given in the table, even though the reported uncertainty estimates for several of the experimental values were smaller than 0.5 kcal/mol.

*From ref. 13.

^†From estimates calculated in ref. 7.

^‡Values that have not been directly measured.

^§From data presented in figure 1B of ref. 12, recalculated with a dimerization free energy ΔG_dim = −11.0 kcal/mol (36) and setting O_L12_coop = O_R12_coop = −2.7 kcal/mol. The values for O_L cooperativity were not unambiguously determined by Senear et al. (12), but the chosen values reflect our assumptions.

^¶From estimates calculated in ref. 35.