在AA9溶性多糖胺单氧化酶中的第二球丁的旋转体是pH依赖的
Ingvild Isaksen1, Suvamay Jana2, Christina M Payne2
1Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
Biophysical journal
|April 4, 2024
概括
性多糖化单氧化酶 (LPMOs) 使用堆叠胺来稳定生物质转化过程中的关键中间体. 了解其依赖pH的方向对于优化工业应用和自然衰变过程至关重要.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 生物技术是生物技术.
背景情况:
- 性多糖体单氧化酶 (LPMOs) 对于生物聚合物分解和生物质转化至关重要.
- 精确的LPMOs反应机制,特别是保存残留物的作用,仍然不完全理解.
- 一种名为"堆叠胺"的保存胺残留物被提议用于帮助真菌AA9 LPMOs的催化.
研究的目的:
- 为了研究在真菌AA9LPMOs中堆叠histidine的pH依赖的构造动态.
- 阐明堆叠胺在静止 (Cu(II)) 和活性 (Cu(I)) LPMO形式中的质子化状态的作用.
- 为了澄清堆叠胺对LPMO催化机制和基质相互作用的贡献.
主要方法:
- 使用了恒定pH和加速分子动力学模拟.
- 在不同的质子状态中监测了堆叠的histidine的动态.
- 对两种真菌LPMOs的Cu (II) 和Cu (I) 形式进行了模拟.
主要成果:
- 质子堆叠的histidine采用一个向外的形状,远离活性部位,与实验数据一致.
- 在中性pH值或与纤维素结合时,在堆叠方向上仅观察到histidine的HIE (中性) 质子状态.
- 堆叠的胺可以稳定溶液中的Cu(II) - 超氧中间体,促进H2O2的形成,并在与基质结合时充当稳定剂而不是酸催化剂.
结论:
- 堆叠胺的pH依赖性方向至关重要,应在LPMO反应建模和解释中考虑.
- 了解这些pH效应对于基本的LPMO动力学和工业酶应用都很重要.
- 这些知识有助于理解LPMO在自然过程中的功能,例如真菌木材腐烂.
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