PAM的热力学通过Cas9识别Streptococcus pyogenes
Shreya Bhattacharya1, Keshav Goyal1, Priyadarshi Satpati1
1Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
Journal of chemical information and modeling
|December 1, 2025
概括
这就是CRISPR/Cas9系统.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 杆菌pyogenes CRISPR/Cas9 (SpCas9) 系统是一个强大的基因组编辑工具.
- 对于DNA向,SpCas9需要一个特定的5'-NGG-3'Protospacer相邻动机 (PAM) 序列.
- 了解PAM识别对于SpCas9的准确性和特异性至关重要.
研究的目的:
- 为了研究SpCas9 PAM识别的能量基础.
- 阐明控制SpCas9特异性的结构和热力学因素.
- 为工程设计SpCas9变体提供洞察力,具有改变的PAM特异性.
主要方法:
- 使用化学自由能计算来评估PAM识别强度.
- 热力学分析被用来量化蛋白质-DNA相互作用的能量.
- 计算的自由能量变化 (ΔΔG) 与实验DNA裂变数据的相关性.
主要成果:
- 在NGG PAM序列的第二位和第三位的突变中,SpCas9非常不利.
- 由于形状刚性,在第三个PAM位置的突变中观察到更高的能量惩罚.
- 直接蛋白质-PAM相互作用的破坏和溶剂暴露的增加解释了SpCas9的PAM选择性.
- 计算的ΔΔG值准确地预测了SpCas9在不同PAM序列中的DNA裂变活性.
结论:
- 这项研究揭示了SpCas9 PAM选择性的热力学和结构基础.
- 关键残留物的符合性刚性 (R1335) 显著影响SpCas9的特异性.
- 这些发现为合理设计具有定制PAM识别特性的SpCas9变体提供了基础.
- 这项工作促进了对CRISPR/Cas系统及其基因组编辑应用的理解.
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