FIGURE 8.

UP1 binds the apical loop of SL1^ISS specifically and with high affinity. Calorimetric titrations of UP1-SL1^ISS-33 (A) and UP1-SL1^ISS-25 (B) conducted at 298 K in binding buffer (see “Experimental Procedures”) are shown. Secondary structures of SL1^ISS-33 and SL1^ISS-25 are shown in the insets. The normalized thermograms were fit to a single site binding isotherm. C, plot of the thermodynamic parameters (average ± S.D. (error bars) of three replicates) determined by non-linear fits to the binding isotherms.