设计一个Streptococcus Cas9正义分子与RxQ PAM结合动机,用于在细菌中控制无PAM基因
Yuxi Teng1, Jian Wang1, Tian Jiang1
1School of Chemical, Materials and Biomedical Engineering, College of Engineering, The University of Georgia, Athens, Georgia 30602, United States.
ACS synthetic biology
|August 29, 2023
概括
研究人员发现了一种新的Cas9酶SeHCas9,具有放松的原体空间器相邻动机 (PAM) 要求. 工程变异提供了无PAM的基因编辑,扩大了细菌基因控制的可能性.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
- 生物技术是生物技术.
背景情况:
- 由RNA引导的Cas9内核酶是基因编辑的强大工具,但受到原体空间邻基因 (PAM) 识别的限制.
- 广泛使用的SpCas9酶需要NGG PAM序列,限制其准范围.
研究的目的:
- 为了克服Cas9酶的PAM限制.
- 识别和表征具有改变PAM特异性的新型Cas9正态.
- 为扩大细菌基因控制的准范围设计Cas9变体.
主要方法:
- 鉴定和表征了来自 *Streptococcus equinus* HC5.5 的 SeHCas9 的正向体.
- 完成了完整的PAM分析,以确定SeHCas9的识别序列.
- 通过分析PAM相互作用域中的关键残留物来研究PAM相互作用机制.
- 通过蛋白质修饰改造SeHCas9变体以改变PAM特异性.
主要成果:
- SeHCas9表现出一个独特的RxQ PAM结合动机,并识别NAG PAM,容纳NKG和NAW PAM.
- 在RxQ基因中的残留物R1336对PAM特异性至关重要,与保留的残留物R1152和Q1229一起.
- 工程变体SeHdCas9-Q1229R和SeHdCas9-RR,在NNG和NNN PAM范围分别表现出强大的抑制.
- 确立了新的Cas9变异,显著减少了PAM限制.
结论:
- 一个新的Cas9 PAM相互作用机制已经被阐明.
- 工程SeHCas9变种提供了扩展的准能力,接近无PAM的基因编辑.
- 这些发现为细菌基因调节提供了先进的工具,具有最小的准约束.
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