由Cas9内核酶识别PAM依赖的目标DNA的结构基础
Carolin Anders1, Ole Niewoehner1, Alessia Duerst1
1Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
Nature
|August 1, 2014
概括
克里斯普尔-Cas9系统使用导向RNA在特定位置切割DNA. 这项研究揭示了Cas9与DNA结合的晶体结构,详细介绍了它如何识别PAM序列以进行精确的基因组编辑.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 遗传学 是一个遗传学.
背景情况:
- 与CRISPR相关的蛋白9 (Cas9) 是一种RNA引导的内核酶,对于基因组编辑至关重要.
- Cas9的功能依赖于在目标DNA中识别原空间体相邻基因 (PAM).
- 了解Cas9-DNA相互作用对于推进基因编辑技术至关重要.
研究的目的:
- 为了阐明Streptococcus pyogenes Cas9 (SpCas9) 识别正规5'-NGG-3' PAM序列的结构基础.
- 为了解依赖PAM的DNA解和RNA-DNA杂交的形成提供一个结构框架.
- 为设计具有改变PAM特异性的SpCas9变体奠定基础.
主要方法:
- 使用X射线结晶学来确定SpCas9.9的结构.
- 这项研究利用了SpCas9的复合物,一种单分子导向RNA,以及具有NGG PAM的向DNA.
- 结构分析的重点是SpCas9,引导RNA,向DNA和PAM序列之间的相互作用.
主要成果:
- 晶体结构揭示了PAM图案位于一个基配对DNA复合体内.
- 在Cas9的C端域中保存的氨酸残留物通过主要沟相互作用与PAM的GG二核酸相互作用.
- 与PAM双重小沟和+1基集团的相互作用促进了PAM上游的局部DNA链分离.
结论:
- 这些发现表明,在CRISPR-Cas9活动期间,PAM-依赖的DNA化和随后的RNA-DNA杂交形成的机制存在.
- 这种结构洞察力为合理设计具有修改PAM特异性的Cas9酶提供了基础.
- 这项研究增强了我们对CRISPR-Cas9基因组编辑背后的基本分子机制的理解.
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