AcrIF9 tethers non-sequence specific dsDNA to the CRISPR RNA-guided surveillance complex
AcrIF9 tethers non-sequence specific dsDNA to the CRISPR RNA-guided surveillance complex
复制标题
DOI：
10.1038/s41467-020-16512-1
复制
发表时间：
2020-06-01
影响因子：
16.6
通讯作者：
Wiedenheft, Blake
中科院分区：
文献类型：
--
作者：
Hirschi, Marscha;Lu, Wang-Ting;Wiedenheft, Blake
细菌已经进化出复杂的适应性免疫系统，称为CRISPR-CA，可以提供针对噬菌体感染的特定序列保护。反过来，噬菌体进化出了一系列抑制这些免疫系统的抗CRISPR。在这里，我们报道了抗CRISPR蛋白IF9(AcrIF9)与I-F型CRISPR RNA引导的监视复合体(CSY)的结构。除了立体阻断互补dsDNA与CRISPR RNA的杂交外，我们的结果表明AcrIF9结合也促进了与dsDNA的非序列特异性结合，潜在地将复合体与靶DNA隔离。这些发现突出了噬菌体用来抑制CRISPR介导的免疫系统的抗CRISPR机制的多功能性。
Bacteria have evolved sophisticated adaptive immune systems, called CRISPR-Cas, that provide sequence-specific protection against phage infection. In turn, phages have evolved a broad spectrum of anti-CRISPRs that suppress these immune systems. Here we report structures of anti-CRISPR protein IF9 (AcrIF9) in complex with the type I-F CRISPR RNA-guided surveillance complex (Csy). In addition to sterically blocking the hybridization of complementary dsDNA to the CRISPR RNA, our results show that AcrIF9 binding also promotes non-sequence-specific engagement with dsDNA, potentially sequestering the complex from target DNA. These findings highlight the versatility of anti-CRISPR mechanisms utilized by phages to suppress CRISPR-mediated immune systems.