An amino acid binding protein involved in transport of the amino acid across membranes was isolated from E. coli. Equilibrium dialysis measurements at 25°C and 37°C yielded dissociation constant (Ks) values of 5.0 x 10-6 M and 2.0 x 10-5 M, respectively, for the protein-amino acid complex.
a. What are the ΔG°´ values for formation of this complex at 25°C and 37°C?
b. What are ΔH°´ and ΔS°´ for this binding reaction assuming that they are constant over this temperature range?
c. Is this amino acid binding driven by entropy or enthalpy? Explain.