Table 1.

Free energies of calcium binding to sites I and II of PCaM1–75

Protein	ΔG1a	ΔG2	ΔGcb
WT	−5.59 ± 0.26	−12.79 ± 0.04	−2.42 ± 0.56
V35I/D50N	−5.98 ± 0.28	−12.74 ± 0.14	−1.60 ± 0.52
G40E	−5.82 ± 0.20	−13.16 ± 0.07	−2.33 ± 0.37
G40E/D50N	−5.74 ± 0.12	−13.34 ± 0.10	−2.69 ± 0.18
D50G	−5.23 ± 0.58	−12.96 ± 0.09	−3.32 ± 1.22
E54K	−5.64 ± 0.08	−12.58 ± 0.04	−2.10 ± 0.10
G59S	−5.62 ± 0.14	−12.66 ± 0.04	−2.24 ± 0.28

^a Gibbs free energies (in kcal/mole (1 kcal = 4.184 J)) are described according to equation 1. Free energies and errors represent averages and standard deviations between four trials. The √var for each trial ranged from 0.008 to 0.063, with an average of 0.024.

^b Estimate of cooperative free energy is described by equation 3.