基于分子动力学的脂肪酶Lipase 5的热稳定性研究

天然的低温脂肪酶往往结构热稳定性比较差,制约了其长时间有效地发挥催化作用及保存.该研究以来源于白色念珠菌(Candida albicans)的低温脂肪酶Lipase 5为对象,运用相关分子动力学方法进行研究,提出了提高其热稳定性的理论策略.首先运用同源建模方法构建目标蛋白的三维结构模型;然后通过18ns分子动力学模拟,锚定目标蛋白不稳定区域中柔性氨基酸(甘氨酸)的位置,并将这些柔性氨基酸位点突变为刚性氨基酸(脯氨酸);最后利用分子动力学模拟来验证这些突变对蛋白质热稳定性的影响.结果发现,将Lipase 5三维结构中的第279位甘氨酸突变为脯氨酸后,使得蛋白质热稳定性增强.这为类似低温脂肪酶的热稳定性改造的实验设计提供了理论支持.

Molecular Dynamics Method on Thermostability of Cold Active Lipase 5

The thermostability of naturally cold-adapted lipases is often relatively poor, limiting their long catalytic effect and long-term preservation. In the current study, one cold-adapted lipase Lipase 5 from Candida albicans was investigated by means of molecular dynamics method in order to improve its thermal stability. First the three-dimensional model of Lipase 5 was constructed by homology modeling. Then 18ns molecular dynamics simulations were utilized to find the unstable region in Lipase 5 out of the protein active center with high conformational fluctuations, and one possible mutant site 279-Gly was detected. It is finally proved that mutation of flexible 279-Gly to rigid Proline endows Lipase 5 enhanced thermostability. Our finds may provide theoretical direction and support to design experiments of reforming thermal stability of cold active lipases.