通过使用与Ca2+结合的中间状态对转谷氨酶2活性进行Ca2+依赖调节的结构和机制分析
Agnele S Sewa1, Harrison A Besser2,3, Irimpan I Mathews4
1Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305.
概括
这项研究揭示了与结合的转谷氨酶2 (TG2) 的结构,这对乳病的发病过程至关重要. 这些发现解释了TG2如何形成必要的中间体,并提供了对疾病机制的见解.
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:
- 哺乳动物转质氨酶,包括转质氨酶2 (TG2),是参与各种疾病的依赖的酶.
- 乳病 (CeD) 的发病过程涉及TG2去amidating质,形成反应性g-glutamyl thioester中间体.
- 了解TG2的作用需要对其结状态的结构洞察.
研究的目的:
- 为了确定人体TG2与离子结合的X射线晶体结构,以及一种质胺抑制剂.
- 阐明TG2催化脱化和转化反应的结构基础.
- 为提供对TG2在腹腔疾病中的作用的机制性理解.
主要方法:
- 人类TG2的X射线晶体学复合体与胺抑制剂和Ca2+离子.
- 结构引导的生物化学实验.
- 酶基质和酶抑制剂相互作用的分析.
主要成果:
- 该结构显示了S1和S3位点的Ca2 + 结合,解释了二硫化物键形成的调节和硫化物键形成的必要性.
- 确定了关键残留物 (H305,E363),对转化而不是脱化至关重要.
- 发现的残留物 (N333,K176) 通过键稳定TG2基质/抑制剂.
- 报道的中间状态调节器是TG2反应过渡状态的高级模型.
结论:
- 该结构为TG2的催化活性及其在乳病中的作用提供了机制基础.
- 这些发现凸显了铁中间体在TG2介导的病原发生过程中的重要性.
- 这项工作为开发向TG2抑制剂提供了基础.
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