在催化周转过程中,谷氨素的毫秒动力学取决于基质结合,在静止状态中不存在
Kristine Steen Jensen1, Jakob R Winther, Kaare Teilum
1Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark.
Journal of the American Chemical Society
|February 18, 2011
概括
酶的结构动态是功能的关键. 这项研究揭示了葡萄糖素的存在.
科学领域:
- 生物化学 生化学
- 酶学 是一种酶学.
- 结构生物学 结构生物学
背景情况:
- 酶形态动力学对于催化效率至关重要,但涉及的特定运动仍然不太了解.
- 了解酶运动对于设计更有效的酶抑制剂和催化剂至关重要.
研究的目的:
- 调查谷氨素在其催化周期中的构造动态的作用.
- 为了确定酶运动是否与催化周转和基质结合直接相关.
主要方法:
- 利用了核磁共振 (NMR) 技术,包括磁化转移和R(2) 放松分散.
- 采用了配体定位实验和生化调节来控制酶的催化速率.
- 使用 (15)N核自旋放松分散,监测蛋白质骨干结构变化.
主要成果:
- 在23种残留物中观察到两种状态的构造过渡,与谷氨酸的交换率直接相关.
- 证明基质结合 (减少的谷氨) 可以竞争性地抑制酶,反映催化动力学.
- 在酶的静止状态中没有发现任何显著的脊柱运动,这表明没有替代适合物的积累.
结论:
- 葡萄糖素中的酶循环率是由生产性酶基质复合物的形成决定的.
- 催化是通过诱导适合机制进行的,而不是通过选择先前存在的形态状态.
- 在催化过程中,特定的蛋白质骨干运动与基质结合和循环相结合.
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