Figure 3.

Correlation plots of ClpXP-mediated proteolysis rates, V_max, with respect to intrinsic unfolding rate $k_u^{H_{2}O}$. The data points of UCHs and GFP are shown in open circles with their radii proportional to the free energy of unfolding ΔG_GdnHCl as indicated on the left. Since UCHL1 variants exhibited a three-state equilibrium (Table S1), their radii correspond to the sum of ΔG_N-I and ΔG_I-D. Furthermore, the data points are color-ramped from blue to grey to red according to their melting temperatures, T_m, as indicated on the right. The linear regression of the double-log plot of UCHs data points yields a slope of 1.48 ± 0.18 and a log($k_u^{H_{2}O}$) intercept of −3.10 ± 0.31 when log(V_max) = 0 (R² = 0.96), shown in solid black line. The previously reported data of Arc (cyan triangles), titin I27 (Titin; grey squares) and GFP (inverted green triangles) are shown for comparison (Table S4).