The interaction of α-chymotrypsin with one persistent organic pollutant (dicofol): Spectroscope and molecular modeling identification

Great attention is devoted to persistent organic pollutant (POP), among which the pesticide dicofol is critical related to food safety and might raise the risk of cancer incidence. To take a comprehensive evaluation of its toxicity, we investigated its interaction with a serine protease α-chymotrypsin by multi-spectroscopic techniques and molecular modeling method. UV-vis absorption, synchronous fluorescence, and circular dichroism data elucidated that dicofol unfolded the framework of α-chymotrypsin and led to secondary structure changes. The fluorescence and lifetime assay determined the static quenching mode and binding parameters. As an auxiliary method, molecular modeling has displayed the specific binding site and information about binding forces and drug-residues distances which were consistent with conclusions from above. Additional, enzyme activity assay gave evidence at the functional aspect to clarify the fact that dicofol could contribute to the conformational changes and furthermore alter the function of the enzyme.

The pesticide dicofol could interact with α-chymotrypsin, a serine protease, to form a stable complex which leads to conformational and functional changes of the enzyme. To take a comprehensive evaluation of the potential toxicity of dicofol, we investigated the interaction by multi-spectroscopic techniques and molecular modeling study. Molecular modeling has displayed the specific binding site and given information about binding forces and drug-residues distances which are in accordance with conclusions from spectroscopic experiments. Besides, enzyme activity assay has given evidence from the functional aspect to clarify the fact that dicofol can not only contribute to the conformational changes of protein but also alter the enzyme function.Highlights► We assess the interaction of dicofol with α-chymotrypsin in molecular level. ► We examine regular changes of conformation and function of α-CT affected by DCF. ► Molecular modeling provides auxiliary and consistent information of α-CT changes. ► The intake of DCF may lead to similar effect on other serine proteases.