FIGURE 3.

Determination of binding constant and thermodynamics of the LigBCen2NR/NTD interaction by ELISA and ITC. A, binding of serial concentrations of LigBCen2NR to immobilized NTD by ELISA. Serial concentrations of GST-LigBCen2R, GST-LigBCen2NR, GST-LigBCen2 (positive reference), or GST-LigCon (negative reference) were added to 1 μm NTD- or bovine serum albumin-coated wells (negative control; data not shown). B, determination of the binding affinity by ITC. The cell contained 1 ml of NTD, and the syringe contained 250 μl of LigBCen2NR. Top, heat differences obtained from 25 injections of LigBCen2NR; bottom, integrated curve with experimental data (♦) and the best fit (line). The thermodynamic parameters are shown in Table 1.