5XWP

Crystal structure of LbuCas13a-crRNA-target RNA ternary complex

Summary for 5XWP

• Entry DOI: 10.2210/pdb5xwp/pdb
• Descriptor: Uncharacterized protein, RNA (59-MER), RNA (30-MER), ... (4 entities in total)
• Functional Keywords: lbucas13a, c2c2, crrna, target rna, rna binding protein-rna complex, rna binding protein/rna
• Biological source: Leptotrichia buccalis; More
• Total number of polymer chains: 6
• Total formula weight: 336354.33

Authors

Liu, L.,Li, X.,Li, Z.,Wang, Y. (deposition date: 2017-06-30, release date: 2017-09-13, Last modification date: 2017-10-18)

Primary citation

Liu, L.,Li, X.,Ma, J.,Li, Z.,You, L.,Wang, J.,Wang, M.,Zhang, X.,Wang, Y.
The Molecular Architecture for RNA-Guided RNA Cleavage by Cas13a.
Cell, 170:714-726.e10, 2017

PubMed Abstract: Cas13a, a type VI-A CRISPR-Cas RNA-guided RNA ribonuclease, degrades invasive RNAs targeted by CRISPR RNA (crRNA) and has potential applications in RNA technology. To understand how Cas13a is activated to cleave RNA, we have determined the crystal structure of Leptotrichia buccalis (Lbu) Cas13a bound to crRNA and its target RNA, as well as the cryo-EM structure of the LbuCas13a-crRNA complex. The crRNA-target RNA duplex binds in a positively charged central channel of the nuclease (NUC) lobe, and Cas13a protein and crRNA undergo a significant conformational change upon target RNA binding. The guide-target RNA duplex formation triggers HEPN1 domain to move toward HEPN2 domain, activating the HEPN catalytic site of Cas13a protein, which subsequently cleaves both single-stranded target and collateral RNAs in a non-specific manner. These findings reveal how Cas13a of type VI CRISPR-Cas systems defend against RNA phages and set the stage for its development as a tool for RNA manipulation.

PubMed: 28757251
DOI: 10.1016/j.cell.2017.06.050

Experimental method

X-RAY DIFFRACTION (3.086 Å)