2024年8月28日，来自美国麻省理工学院张锋研究组在学术期刊《细胞》上发表了标题为“Structural insights into the diversity and DNA cleavage mechanism of Fanzor.”的研究成果，揭示Fanzor的多样性及其DNA切割机制的结构性见解。
据介绍，Fanzor是一种由ωRNA引导的核酸内切酶，广泛存在于真核生物中，具有独特的基因编辑潜力。
研究人员描述了来自三种不同生物的Fanzor（Fz）结构。研究人员发现，尽管不同物种的ωRNA长度差异显著，但Fanzor共享一个通用的ωRNA相互作用界面。分析还揭示了Fanzor的DNA识别和解链能力以及非典型催化位点的存在。
结构展示了Fanzor蛋白构象如何变化，以允许双链DNA在R环内结合到活性位点。机制上，对不同状态下的结构进行检查显示，RuvC结构域上的盖环构象受引导/DNA异源双链形成的控制，从而调节核酸酶的活化以及单一切割位点的DNA双链置换。这些研究结果阐明了Fanzor的机制，为工程应用奠定了基础。
Highlights
•Cryo-EM structures of Fanzor from three organisms in different conformational states
•Structures reveal common features and structural diversity of Fanzor
•Local conformational changes regulate target DNA manipulation by Fanzor
Summary
Fanzor (Fz) is an ωRNA-guided endonuclease extensively found throughout the eukaryotic domain with unique gene editing potential. Here, we describe the structures of Fzs from three different organisms. We find that Fzs share a common ωRNA interaction interface, regardless of the length of the ωRNA, which varies considerably across species. The analysis also reveals Fz’s mode of DNA recognition and unwinding capabilities as well as the presence of a non-canonical catalytic site. The structures demonstrate how protein conformations of Fz shift to allow the binding of double-stranded DNA to the active site within the R-loop. Mechanistically, examination of structures in different states shows that the conformation of the lid loop on the RuvC domain is controlled by the formation of the guide/DNA heteroduplex, regulating the activation of nuclease and DNA double-stranded displacement at the single cleavage site. Our findings clarify the mechanism of Fz, establishing a foundation for engineering efforts.
文章来源：
Peiyu Xu, Makoto Saito, Guilhem Faure et al, Structural insights into the diversity and DNA cleavage mechanism of Fanzor.DOI: 10.1016/j.cell.2024.07.050,Cell：最新IF：66.85
