The temperature dependence of changes in the free energies for the dimeric association of βB1 and βA3 and the tetrameric association of βB1/βA3.

<p>Asssociation of βB1, βA3 and βB/βA3 are shown by blue open triangles, black open squares and red open circles, respectively. Panels A and B: van't Hoff plots where <i>ln(K_d/C_o)</i> is plotted as function of the reciprocal of absolute temperature (<i>1000/T</i>), <i>K_d's</i> are the dissociation constants obtained from analytical ultracentrifugation, and <i>C_o</i> is the µM concentration. Panel A: the difference in heat capacity (<i>ΔC_p</i>) is constrained to be 0, resulting in a linear function; Panel B: <i>ΔC_p</i> is not constrained and has a nonzero value. Panel C: temperature dependence of Gibbs free energy gained in formation of βB1/βA3. <i>ΔΔG_d (βB1/βA3)</i> is defined as a difference between Gibbs free energy changes of tetrameric βB1/βA3 and that of individual components (βB1 and βA3). Concentrations for βB1, βA3, and βB1/βA3 crystallins were each 0.5 mg/ml.