Abstract:For investigating the effects of pH on the binding between protein and polyphenols. The binding energy and binding mechanism between epigallocatechin gallate(EGCG) and β--lactoglobulin at pH 2, 5 and 8 were respectively studied using molecular docking and molecular dynamics simulation. EGCG mainly bound to 3 sites of β--lactoglobulin. The docking site with the highest binding energy was used for 150 ns molecular dynamics simulation. It was found that the fluctuation of small molecules was larger than that of protein, especially at pH 2, however, the fluctuation of small molecules did not affect the stability of protein structure. The hydrophobic surface area, the content of α-helix and β--sheet of protein were lowest at pH 5. The highest binding free energy of small molecules to protein was detected at pH 5, while the lowest at pH 8. The highest value was mainly due to the strongest hydrophobic force, hydrogen bond and van der Waals force at pH 5. The difference of pH would affect the surface structure of protein, especially the binding site, thus affecting the binding energy, binding site, and binding posture between protein and small molecule.
