Structure Studies of the CRISPR-Csm Complex Reveal Mechanism of Co-transcriptional Interference
Lilan You, Jun Ma, Jiuyu Wang, Konstantin Severinov, Xinzheng Zhang, Yanli Wang
Summary
Csm, a type III-A CRISPR-Cas interference complex, is a CRISPR RNA (crRNA)-guided RNase that also possesses target RNA-dependent DNase and cyclic oligoadenylate (cOA) synthetase activities. However, the structural features allowing target RNA-binding-dependent activation of DNA cleavage and cOA generation remain unknown. Here, we report the structure of Csm in complex with crRNA together with structures of cognate or non-cognate target RNA bound Csm complexes. We show that depending on complementarity with the 5′ tag of crRNA, the 3′ anti-tag region of target RNA binds at two distinct sites of the Csm complex. Importantly, the interaction between the non-complementary anti-tag region of cognate target RNA and Csm1 induces a conformational change at the Csm1 subunit that allosterically activates DNA cleavage and cOA generation. Together, our structural studies provide crucial insights into the mechanistic processes required for crRNA-meditated sequence-specific RNA cleavage, RNA target-dependent non-specific DNA cleavage, and cOA generation.
附件下载：
Structure Studies of the CRISPR-Csm Complex Reveal Mechanism of Co-transcriptional Interference, Cell, 29 Nov 2018
Cell, 29 November 2018，DOI: https://doi.org/10.1016/j.cell.2018.10.052
Structure Studies of the CRISPR-Csm Complex Reveal Mechanism of Co-transcriptional Interference
Lilan You, Jun Ma, Jiuyu Wang, Konstantin Severinov, Xinzheng Zhang, Yanli Wang
Summary
Csm, a type III-A CRISPR-Cas interference complex, is a CRISPR RNA (crRNA)-guided RNase that also possesses target RNA-dependent DNase and cyclic oligoadenylate (cOA) synthetase activities. However, the structural features allowing target RNA-binding-dependent activation of DNA cleavage and cOA generation remain unknown. Here, we report the structure of Csm in complex with crRNA together with structures of cognate or non-cognate target RNA bound Csm complexes. We show that depending on complementarity with the 5′ tag of crRNA, the 3′ anti-tag region of target RNA binds at two distinct sites of the Csm complex. Importantly, the interaction between the non-complementary anti-tag region of cognate target RNA and Csm1 induces a conformational change at the Csm1 subunit that allosterically activates DNA cleavage and cOA generation. Together, our structural studies provide crucial insights into the mechanistic processes required for crRNA-meditated sequence-specific RNA cleavage, RNA target-dependent non-specific DNA cleavage, and cOA generation.
文章链接：https://www.cell.com/cell/fulltext/S0092-8674(18)31451-X#%20
相关报道：http://www.ibp.cas.cn/kyjz/zxdt/201811/t20181130_5201270.html