Figure 3.

RecO binds to the IDL peptides only via the acidic tip. (A) Panels i–iii show the results of ITC studies of the binding of P15, P31 and P65 peptides to RecO, respectively. The peptides (40–50 μM) were titrated into RecO (2 μM) in buffer BTP (pH 8.0, 50 mM NaCl) at 25°C. The smooth curves are simulations for a 1:1 binding model using the best fit binding parameters indicated in each panel (see also Table 1 and Supplementary Table S1). (B) Values of ΔG° (blue), ΔH (orange) and TΔS° (gray) obtained from ITC experiments for P15 (○), P31 (Δ) and P65 (□) peptides binding to RecO performed at the indicated temperatures. Solid lines show fits of the data with linear regression. The raw data are shown in Supplementary Figure S3.