爪型环的氨酸突变加速了细胞生物水解酶的催化
Zhiyou Zong1, Qiyu Li1, Zhangyong Hong1
1State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry , Nankai University , Tianjin 300071 , P. R. China.
Journal of the American Chemical Society
|August 22, 2019
概括
研究人员在纤维素降解酶 (GH7 CBHI) 中发现了一种"爪臂"机制, 一个特定的 lysine 突变显著提高了酶活性和纤维素降解,为提高酶效率提供了策略.
科学领域:
- 生物化学
- 酵素学
- 分子生物学
背景情况:
- 在生物质转化过程中,纤维素由糖化酶家族7 (GH7) 纤维化酶I (CBHI) 降解至关重要.
- 加快CBHI的催化循环是提高酶效率和降低成本的关键.
- 了解产品排放机制对于酶工程至关重要.
研究的目的:
- 研究加速GH7CBHI催化循环的新方法.
- 阐明细胞质排放的机制及其对酶活性的影响.
- 为了提高纤维素降解的工程 GH7 CBHI.
主要方法:
- 在GH7CBHI上进行了广泛的分子动力学 (MD) 模拟 (12-μs).
- 计算分析发现了一种"爪臂"机制,其中包括一个灵活的循环和一个关键残留物 (Thr389).
- 使用量子力学/分子力学 (QM/MM) 计算和定位突变 (lysine突变物).
主要成果:
- 鉴定出一种用于细胞菌驱逐的新型"爪臂"机制,其中包括一个灵活的循环作为"手臂"和残留物Thr389作为"爪".
- Thr389的氨酸突变显著加快了细胞质排放和多糖链转位.
- QM/MM 计算显示,氨酸替代剂降低了 2.3 kcal/mol 的糖化障碍.
- 实验验证证了* Talaromyces emersonii* CBHI (TeCel7A) 的更高的酶反应率和更高的细胞酶产量.
结论:
- "爪臂"作用和特定的氨酸突变是增强GH7CBHI活性的一种可行的策略.
- 具有加速细胞质解离的工程 GH7 CBHI 显示了提高纤维质降解效率.
- 这项研究为设计更有效,更经济的纤维素降解酶提供了洞察力.
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