Fig. 4.
Calorimetric analysis of the interaction of E. coli PNPase and RNase E recognition micro-domain (residues 1021–1061). Top panel: The isothermal calorimetry profile showing the heat released upon titrating RNase E micro-domain with PNPase core. Bottom panel: The integrated heats after correction for heat of dilution. The data are best fit with a single binding site model, yielding parameters N = 1.02 ± 0.02, Ka 9.56 ( ± 0.71) × 105 M-1, ΔH = –21.48 ± 0.52 kcal mol–1, ΔS = -44.7 cal mol–1 K–1.