To reveal the binding mechanism of CPS4 with them, fluorescent quenching, UV absorption spectra, circular dichroism (CD) spectra, isothermal titration calorimetry (ITC), molecular docking, molecular dynamic (MD) simulation, and site-directed mutagenesis were applied.  The observed △H < 0 and △S > 0 of thermodynamics suggest the main driving forces are electrostatic or hydrophobic force.  All above thermodynamics findings are in line with the results of ITC experiments.  Furthermore, molecular docking, MD simulation and site-directed mutagenesis indicate the binding cavities are located at cavity 1 in C-terminal of CSP4, where Tyr98 and Asp67 are vital amino acids in maintaining the stable form of protein and larval pheromones, and electrostatic energies are the main driving forces. 
THERM