通过X射线结晶学和分子动力学模拟,可视化协价中间体和烯利用A的构造状态
David P Buckley1, Donald F Becker2, John J Tanner3
1Department of Biochemistry, University of Missouri, Columbia, Missouri, USA.
The Journal of biological chemistry
|July 30, 2025
概括
双功能的酶氨酸利用A (PutA) 使用不同的域将L-氨酸转化为L-氨酸. 结构和模拟研究揭示了中间体如何在酶内道化,支持基质道化机制.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 酶学 是一种酶学.
背景情况:
- 双功能酶普林利用A (PutA) 对于L-普林代谢至关重要.
- 它包括氨酸脱酶 (PRODH) 和L-glutamate-γ-semialdehyde脱酶 (GSALDH) 域,通过中间通道道连接.
- 假设像Δ1P-pyrroline-5-carboxylate (P5C) 和L-glutamate-γ-semialdehyde (GSAL) 这样的中间体被道化.
研究的目的:
- 阐明来自Sinorhizobium meliloti (SmPutA) 的PutA的催化机制和基质道化.
- 捕捉催化状态的高分辨率结构,并分析酶内的中间运动.
主要方法:
- 采用X射线晶体学,在各种催化阶段获得SmPutA的高分辨率结构 (1.47-1.88 Å).
- 进行了分子动力学模拟 (21×2μs轨迹),从与P5C结合的缩小SmPutA结构开始.
- 量子力学电子结构计算被用于与观察到的引证进行比较.
主要成果:
- 高分辨率结构揭示了关键的催化状态,包括一种新的FADH-proline附加物和结合中间体 (P5C,GSAL).
- GSALDH域结构与化脱酶超级家族内的已知机制保持一致.
- 分子动力学模拟表明P5C扩散到酶道中,支持基质通道并揭示构造变化,包括离子对门动力学.
结论:
- 这项研究为PutA催化循环和基质通道机制提供了原子层面的见解.
- 证据支持通过酶的内部道有效道化中间体的假设.
- 构造动力学,包括离子对门调制,是基质道化过程的组成部分.
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