作为一种酸催化剂的关键活性部位谷氨酸的普遍性在氨酸氧甲基转移酶功能中
Victoria N Drago1, Robert S Phillips2,3, Andrey Kovalevsky1
1Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge TN 37831 USA kovalevskyay@ornl.gov.
Chemical science
|August 16, 2024
概括
血清基甲基转移酶 (SHMT) 对癌症代谢至关重要. 中子晶体学揭示了Glu53的关键质子化状态和催化作用,有助于设计向癌症疗法.
科学领域:
- 生物化学 生化学
- 结构生物学 结构生物学
- 酶学 是一种酶学.
背景情况:
- 血清甲基转移酶 (SHMT) 在单碳代谢中至关重要,使用维生素B6 (PLP) 和B9 (THF) 共酶.
- 在癌症代谢重编程中SHMT的作用使其成为抗代谢剂化疗的目标.
研究的目的:
- 阐明SHMT的催化机制,用于设计特定的抑制剂.
- 用中子晶体学来确定SHMT活性部位的质子化状态.
主要方法:
- 用PLP和叶酸 (FA) 进行*Thermus thermophilus* SHMT (TthSHMT) 的室温中子晶体学.
- 对TthSHMT和人类线粒体SHMT2 (hSHMT2) 三元复合物的X射线晶体学.
主要成果:
- 在TthSHMT活性部位中直接确定H原子位置,包括PLP和FA.
- 观察到质子化催化Glu53,在FA结合时显示质子化状态的变化.
- 确定了关闭环形状的变化,并提出Glu53作为通用酸催化剂.
结论:
- 结构洞察力有助于设计用于癌症治疗的SHMT特异性抑制剂.
- 在THF依赖的和独立的SHMT活动中,Glu53起着至关重要的作用.
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