FIG 4 .
Isothermal titration calorimetry analysis of HK-RR binding affinity. Thermograms and binding isotherms for the cognate CrdS-CrdA TCS pair (A), the noncognate CrdS-RR468 pair (B), and the noncognate HK853-CrdA pair (C) are shown. Enthalpy and Kd for binding were determined using isothermal titration calorimetry in a VP-ITC microcalorimeter as described in Materials and Methods. The top portion of each panel shows baseline corrected thermograms. The bottom portion shows the corresponding binding isotherms generated using nonlinear binding models.