7DMQ

Cryo-EM structure of LshCas13a-crRNA-anti-tag RNA complex

Summary for 7DMQ

• Entry DOI: 10.2210/pdb7dmq/pdb
• EMDB information: 30767
• Descriptor: CRISPR/Cas system Cas13a, CRISPR RNA, Anti-tag target RNA (3 entities in total)
• Functional Keywords: type vi-a crispr-cas system, cas13a, anti-tag rna, inhibition, immune system, immune system-rna complex, immune system/rna
• Biological source: Leptotrichia shahii; More
• Total number of polymer chains: 3
• Total formula weight: 197146.77

Authors

Wang, B.,Zhang, T.,Ding, J.,Patel, D.J.,Yang, H. (deposition date: 2020-12-05, release date: 2021-02-10, Last modification date: 2024-03-27)

Primary citation

Wang, B.,Zhang, T.,Yin, J.,Yu, Y.,Xu, W.,Ding, J.,Patel, D.J.,Yang, H.
Structural basis for self-cleavage prevention by tag:anti-tag pairing complementarity in type VI Cas13 CRISPR systems.
Mol.Cell, 81:1100-, 2021

PubMed 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 LshCas13a 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.

PubMed: 33472057
DOI: 10.1016/j.molcel.2020.12.033

Experimental method

ELECTRON MICROSCOPY (3.06 Å)