Structural basis for self-cleavage prevention by tag:anti-tag pairing complementarity in type VI Cas13 CRISPR systems Journal Article
| Authors: | Wang, B.; Zhang, T.; Yin, J.; Yu, Y.; Xu, W.; Ding, J.; Patel, D. J.; Yang, H. |
| Article Title: | Structural basis for self-cleavage prevention by tag:anti-tag pairing complementarity in type VI Cas13 CRISPR systems |
| Abstract: | Bacteria and archaea apply CRISPR-Cas surveillance complexes to defend against foreign invaders. These invading genetic elements are captured and integrated into the CRISPR array as spacer elements, guiding sequence-specific DNA/RNA targeting and cleavage. Recently, in vivo studies have shown that target RNAs with extended complementarity with repeat sequences flanking the target element (tag:anti-tag pairing) can dramatically reduce RNA cleavage by the type VI-A Cas13a system. Here, we report the cryo-EM structure of Leptotrichia shahii LshCas13acrRNA in complex with target RNA harboring tag:anti-tag pairing complementarity, with the observed conformational changes providing a molecular explanation for inactivation of the composite HEPN domain cleavage activity. These structural insights, together with in vitro biochemical and in vivo cell-based assays on key mutants, define the molecular principles underlying Cas13a's capacity to target and discriminate between self and non-self RNA targets. Our studies illuminate approaches to regulate Cas13a's cleavage activity, thereby influencing Cas13a-mediated biotechnological applications. Extended complementarity between crRNA and anti-tag target RNA mediates autoimmunity of Cas13a systems. Wang et al. show the structure-function data and reveal the molecular basis for prevention of composite catalytic pocket formation and substrate RNA degradation by anti-tag RNA. © 2020 Elsevier Inc. |
| Keywords: | genetics; mutation; nonhuman; protein domain; metabolism; gene expression; protein binding; in vivo study; in vitro study; gene vector; genetic vectors; molecular cloning; cloning, molecular; bacterial protein; chemistry; bacterial proteins; nucleotide sequence; escherichia coli; recombinant proteins; substrate specificity; recombinant protein; base sequence; binding site; base pairing; models, molecular; binding sites; conformational transition; conformation; nucleic acid conformation; enzyme specificity; protein interaction domains and motifs; molecular model; rna cleavage; deoxyribonuclease; endodeoxyribonucleases; cryoelectron microscopy; alpha helix; crispr-associated proteins; leptotrichia; guide rna; rna, guide; article; crispr associated protein; crispr cas system; crispr-cas systems; crispr-cas; protein conformation, alpha-helical; cryo-em structure; cas13; inhibition mechanism; target discrimination |
| Journal Title: | Molecular Cell |
| Volume: | 81 |
| Issue: | 5 |
| ISSN: | 1097-2765 |
| Publisher: | Cell Press |
| Date Published: | 2021-03-04 |
| Start Page: | 1100 |
| End Page: | 1115.e5 |
| Language: | English |
| DOI: | 10.1016/j.molcel.2020.12.033 |
| PUBMED: | 33472057 |
| PROVIDER: | scopus |
| PMCID: | PMC8274241 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 1 April 2021 -- Source: Scopus |
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