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自杀性Arg/N-degron通路ATE1 R-转移酶的结构功能关系
Su Bin Kim1, Ji Su Lee1, Xin Lan2
1Cellular Degradation Biology Center, and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Korea.
Autophagy
|March 18, 2025
概括
甲基转移酶1 (ATE1) 选择性地将氨酸添加到蛋白质中,从而产生N-降解子,这些N-降解子通过ubiquitin-proteasome系统 (UPS) 或自-lysosome系统 (ALS) 准它们进行降解. 结构分析揭示了ATE1的存在.
科学领域:
- 生物化学和分子生物学
- 蛋白质降解途径 蛋白质降解途径
- 结构生物学 结构生物学
背景情况:
- 基转移酶1 (ATE1) 催化N端基转化,产生N-降解子,指导蛋白质降解.
- 通过不同的途径识别N-降解子:无素/Ub-蛋白酶体系统 (UPS) 和自-溶酶体系统 (ALS).
- 尽管ATE1对N端基质的结合亲和力较弱,但ATE1基质选择性的机制仍然不清楚.
研究的目的:
- 阐明ATE1介导的N端 arginylation的结构基础.
- 了解控制ATE1对蛋白质基质的选择性的分子机制.
- 揭示ATE1在UPS和ALS交叉点上的功能.
主要方法:
- 通过冷电子显微镜 (cryo-EM) 确定人类ATE1.1的结构.
- 与Arg-tRNAArg和一个N终端阿斯巴酸盐 (Nt-Asp) 的ATE1复杂的形成.
- 在阿波状态下对ATE1同质化分析.
主要成果:
- 冷-EM结构显示ATE1中的两个相邻的口袋,每个口袋都能够结合N端基质或Arg-tRNA.
- 在ATE1中,一个长而非结构化的循环环绕着Arg-tRNAArg分子.
- ATE1通过多价值相互作用实现基质选择性,在微摩尔范围内具有解离常量 (Kd).
结论:
- 这项研究揭示了通过ATE1.1调解的N端 arginylation的结构原理.
- 多价值相互作用解释了ATE1对特定N端残留物的选择性.
- 这些发现提供了关于ATE1如何通过UPS和ALS整合蛋白质降解信号的见解.
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