Equilibrium binding of tritiated PonA to in vitro -translated EcRs/USP complex of P. xylostella . Protein complex was incubated with different concentrations of tritiated PonA. Non-specific binding was determined using an expression vector. A: Total binding of EcRA+USP. B: Specific binding of EcRB+USP, as was calculated by subtracting the non-specific binding from the total binding. Non-linear curve fitting was plotted through SigmaPlot 11.0 (Systat Software Inc., San Jose, CA). Correlation coefficients (R) for the fitted curves were 0.979(non-specific), 0.987(EcRA+USP), and 0.943(EcRB+USP), respectively.