分子动力学模拟探索乳克鲁维酵母来源的β-半乳糖苷酶热变性条件

The Thermal Denaturation Conditions ofβ-galactosidase in Kluyveromyces lactis under Molecular Dynamics Simulation

为了研究乳克鲁维酵母中β-半乳糖苷酶可能的熔解温度,采用分子动力学模拟的方法,分别对4种不同温度条件下(35、50、65、80℃)的β-半乳糖苷酶进行了50 ns的计算模拟,分析了酶的构象变化以及酶活性中心的差异。研究在原子水平揭示了β-半乳糖苷酶的温度耐受等关键信息:35℃为最适酶活温度,该温度下的β-半乳糖苷酶的整体构象最稳定;该酶在50℃时的原子波动性显著增加,表明此温度可能趋近熔解温度临界值;蛋白在大于65℃条件下丧失柔性,说明蛋白已经变性;进一步的构象分析发现80℃高温会破坏β-D-半乳吡喃糖(GAL)结合位点微环境。

To study the possible melting temperature ofβ-galactosidase in Kluyveromyces lactis,molecular dynamics(MD)simulations at four different temperatures(35,50,65 and 80℃)were performed for 50 ns,respectively.Then the conformational change of the enzyme and the difference of the enzyme active center were analyzed.The crucial information of temperature tolerance ofβ-galactosidase at the atomic level was revealed as follows:the overall conformation ofβ-galactosidase was the most stable at 35℃,which was the optimal temperature for enzyme activity;the atomic fluctuation of the enzyme increased significantly at 50℃,indicating that this temperature may approach the critical value of melting temperature;when the temperature was higher than 65℃,the structure of the protein lost its flexibility,which indicated that the protein had reached the melting temperature.Further conformational analysis showed that the microenvironment ofβ-D-galactopyranose(GAL)binding sites was destroyed at 80℃.