Table 1.

Thermodynamic and kinetic parameters for the crystallization of the HGD, R58H, and R36S proteins

Protein	Ceq(T0), mg/ml	ΔG(T0), kJ⋅mol−1	Ci(T0), mg/ml	Ci/Ceq	ΔH, kJ⋅mol−1
HGD	12.6	−11.7	60–300	4.8–24	−61.5
R58H	0.78	−18.6	25–95	32–122	−76.9
R36S	0.72	−18.8	0.8–0.9	1.1–1.25	−40.4

C_eq(T₀) is the solubility at T₀ (a reference temperature that was taken to be 298 K). ΔG and ΔH are, respectively, the Gibbs free energy and enthalpy of formation of the crystal phase for each protein. C_i(T₀) is the range of initial protein concentrations required to produce crystals at 298 K from pure solutions in approximately 24 h. C_i/C_eq is the corresponding supersaturation, which represents the extent to which the solubility limit must be exceeded for crystals to form. The large difference in ΔH between R58H and R36S reflects the different space groups of these two crystals (ref. 7; C. Slingsby, personal communication).