Department of Environmental Science, School of Environmental and Material Engineering, Yantai University, Yantai, China.
Department of Environmental Engineering, School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Jinan, China.
J Biochem Mol Toxicol. 2019 Feb;33(2):e22248. doi: 10.1002/jbt.22248. Epub 2018 Oct 28.
Because cadmium might interact with proteins and, thus, exert toxicity in organisms, it is vital to understand the molecular mechanism of the interaction between cadmium and biologically relevant proteins as well as the structural and functional changes in these proteins. In this study, the interaction between α-chymotrypsin (α-ChT) and cadmium chloride (CdCl ) was investigated by performing enzyme activity determinations, multispectroscopic measurements, isothermal titration calorimetry, and molecular docking studies. It was demonstrated that CdCl binds to α-ChT mainly via electrostatic forces with (21.0 ± 0.982) binding sites, leading to the increase of α-helix and the decrease of β-sheet. The interaction between CdCl and α-ChT loosened the protein skeleton and increased the molecular volume of α-ChT. CdCl first binds to the interface of α-ChT and then interacts with the key residues His 57 or Asp 102 or both in the active sites, leading to the activity inhibition of α-ChT under the exposure of high CdCl concentrations.
由于镉可能与蛋白质相互作用，从而在生物体中发挥毒性，因此了解镉与生物相关蛋白质之间的相互作用的分子机制以及这些蛋白质的结构和功能变化至关重要。在这项研究中，通过进行酶活性测定、多光谱测量、等温热力学滴定和分子对接研究，研究了α-糜蛋白酶（α-ChT）与氯化镉（CdCl ）之间的相互作用。结果表明，CdCl 通过静电相互作用与α-ChT 结合，主要结合位点为（21.0±0.982）个，导致α-螺旋增加，β-折叠减少。CdCl 与α-ChT 的相互作用使蛋白质骨架变松，增加了α-ChT 的分子体积。CdCl 首先结合在α-ChT 的界面上，然后与活性位点中的关键残基 His 57 或 Asp 102 或两者相互作用，导致在高浓度 CdCl 暴露下α-ChT 的活性受到抑制。
