全球CRISPRRNA导向转子体整合复合物的结构
Jung-Un Park1, Amy Wei-Lun Tsai1, Alexandrea N Rizo1
1Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
Nature
|November 28, 2022
概括
研究人员确定了Scytonema hofmannii与CRISPR相关的转子体 (CAST) 的结构. 这揭示了CAST元素如何整合DNA,为精确的基因组编辑应用提供了洞察力.
科学领域:
- 分子生物学
- 遗传学
- 结构生物学
背景情况:
- 与CRISPR相关的转体子 (CAST) 是移动的遗传元素,它们使用RNA引导的机制来插入大型DNA有效载荷.
- CAST系统包括多个保存的蛋白质,包括一个CRISPR效应器,一个AAA+调节器,一个转位酶和一个与位相关的因子,形成一个转位整合复合体 (转位体).
研究的目的:
- 来自Scytonema hofmannii (ShCAST) 的V-K CAST转基因组的高分辨率结构的复制和确定.
- 阐明ShCAST转基因体内的分子结构和蛋白质-DNA相互作用,为CAST转基因体提供机理性见解.
主要方法:
- 使用单粒子冷电子显微镜 (cryo-EM) 来确定大约1MDa的ShCAST转基因组的结构.
- 生物化学测定用于研究蛋白质-蛋白质和蛋白质-DNA相互作用及其对转移活性的影响.
主要成果:
- 冷-EM结构显示了ShCAST转基因组的模块化组织,详细介绍了Cas12k,TniQ,TnsC和TnsB之间的相互作用.
- Cas12k稳定了R循环结构,而TnsC与TniQ和TnsB相互作用,TnsC-TnsB相互作用刺激了ATPase活性.
- 结构显示TnsC结合的DNA构造变化和对转移至关重要的新蛋白-DNA相互作用,以及灵活的CRISPR效应器关联的证据.
结论:
- 确定的ShCAST转基因结构为V-K CAST系统的组装和功能提供了前所未有的细节.
- 了解这些分子机制为工程 CAST 系统在基因组编辑应用中提高精度打开了道路.
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