Table 4.

Summary of heat capacity changes for binding of biotin and bio-5`-AMP to BirA variants^a

	ΔCp° (biotin) cal/mol/K	ΔCp° (bio-5`-AMP) cal/mol/K
wt	−190 ± 30	−200 ± 50
G115S	−110 ± 20	−220 ± 30
R118G	−80 ± 30	−330 ± 20
R119W	−80 ± 30	−250 ± 50

^a Molar heats of binding were measured by isothermal titration calorimetry at temperatures ranging from 15 to 30°C, and molar heat capacities were obtained from the slopes of the linear dependencies of the binding heat on temperature (Fig. 3 ▶). Each standard molar binding enthalpy used in the analysis represents the average of at least three independent determinations.