Abstract One member of the polychlorinated biphenyls that is linked to a number of human diseases is 3,3′,4,4′,5-pentachlorobiphenyl. Here, density functional theory calculation, molecular simulations and multi-spectroscopic techniques were utilized to evaluate the interaction mechanism of 3,3′,4,4′,5-pentachlorobiphenyl with the pepsin, the digestive enzyme. The results of density functional theory and molecular simulations demonstrated that 3,3′,4,4′,5-pentachlorobiphenyl could be a good candidate for its availability toward pepsin with a frontier orbital gap of 0.18109 eV, and bound to the hydrophobic cavity of pepsin. The steady-state fluorescence and time-resolved fluorescence revealed that the quenching was initiated by complexation of pepsin and 3,3′,4,4′,5-pentachlorobiphenyl with the binding constant of 105 order. The UV-absorption, synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and three-dimensional fluorescence data further confirmed that the changes in the secondary structure of pepsin were induced on the presence of 3,3′,4,4′,5-pentachlorobiphenyl, and a quantitative analysis of the secondary structure elements in pepsin was obtained.

中文翻译：

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胃蛋白酶与 3,3',4,4',5-五氯联苯之间的结合相互作用

摘要 与多种人类疾病有关的多氯联苯中的一个成员是 3,3',4,4',5-五氯联苯。在这里，利用密度泛函理论计算、分子模拟和多光谱技术来评估 3,3',4,4',5-五氯联苯与消化酶胃蛋白酶的相互作用机制。密度泛函理论和分子模拟的结果表明，3,3',4,4',5-五氯联苯可能是胃蛋白酶可用性的良好候选物，前沿轨道间隙为 0.18109 eV，并与胃蛋白酶。稳态荧光和时间分辨荧光表明，淬灭是由胃蛋白酶与 3,3',4,4',5-五氯联苯络合引发的，结合常数为 105 级。紫外线吸收，