Department of Biology, Faculty of Science, University of Shahrekord, Shahrekord, Iran.
Department of Biology, Faculty of Science, University of Payam Noor, Iran.
Int J Biol Macromol. 2018 Jul 15;114:950-960. doi: 10.1016/j.ijbiomac.2018.03.143. Epub 2018 Mar 27.
One of the most important purposes of enzyme engineering is to increase the thermal and kinetic stability of enzymes, which is an important factor for using enzymes in industry. The purpose of the present study is to achieve a higher thermal stability of α-chymotrypsin (α-Chy) by modification of the solvent environment. The influence of sucrose was investigated using thermal denaturation analysis, fluorescence spectroscopy, circular dichroism, molecular docking and molecular dynamics (MD) simulations. The results point to the effect of sucrose in enhancing the α-Chy stability. Fluorescence spectroscopy revealed one binding site that is dominated by static quenching. Molecular docking and MD simulation results indicate that hydrogen bonding and van der Waals forces play a major role in stabilizing the complex. T of this complex was enhanced due to the higher H-bond formation and the lower surface hydrophobicity after sucrose modification. The results show the ability of sucrose in protecting the native structural conformation of α-Chy. Sucrose was preferentially excluded from the surface of α-Chy which is explained by the higher tendency of water toward favorable interactions with the functional groups of α-Chy than with sucrose.
酶工程最重要的目的之一是提高酶的热稳定性和动力学稳定性，这是在工业中使用酶的一个重要因素。本研究的目的是通过修饰溶剂环境来实现α-糜蛋白酶（α-Chy）的更高热稳定性。使用热变性分析、荧光光谱、圆二色性、分子对接和分子动力学（MD）模拟研究了蔗糖的影响。结果表明蔗糖对提高α-Chy 稳定性有影响。荧光光谱揭示了一个主要由静态猝灭主导的结合位点。分子对接和 MD 模拟结果表明氢键和范德华力在稳定复合物中起主要作用。由于蔗糖修饰后形成更多氢键和表面疏水性降低，该复合物的 Tof 得到增强。结果表明蔗糖具有保护α-Chy 天然结构构象的能力。蔗糖优先从α-Chy 的表面排除，这可以解释为水与α-Chy 的功能基团的有利相互作用的趋势高于与蔗糖的相互作用。
