Craspase is a CRISPR RNA-guided and RNA-activated protease — ScienceDaily

Craspase is a CRISPR RNA-guided and RNA-activated protease

A collaboration between researchers from Cornell University Kawaii Long and Stan JJ Brouns of Delft University of Technology in the Netherlands found that Craspase is a CRISPR RNA-guided, RNA-activated protease. The study was published online on August 25, 2022 in the world-leading academic journal Science.

According to the researchers, the type III-E RNA targeting effector complex (gRAMP/Cas7-11) associates with a caspase-like protein (TPR-CHAT/Csx29) to form Craspase (CRISPR-guided caspase).

The researchers used cryo-EM snapshots of Craspase to explain its target RNA cleavage and protease activation mechanisms. Target-guide pairings extending into the 5′ region of the guide RNA replace the gating loop in gRAMP, which initiates extensive conformational relays that heterogeneously calibrate protease catalysis and open an amino acid side-chain-binding pocket. The researchers further defined Csx30 as an endogenous protein substrate that is site-specifically hydrolyzed by RNA-activated Craspase. The activity of this protease is turned off by target RNA cleavage by gRAMP and is not activated by RNA targets containing matching protospacer flanking sequences. Therefore, the researchers believe that Craspase is a target RNA-activated protease with self-regulatory capabilities.

Attachment: English original

Title: Craspase is a CRISPR RNA-guided, RNA-activated protease

Author: Chunyi Hu, Sam PB van Beljouw, Ki Hyun Nam, Gabriel Schuler, Fran Ding, Yanru Cui, Alicia Rodriguez-Molina, Anna C Haagsma, Menno Valk, Martin Pabst, Stan JJ Brouns, Ailong Ke

Issue&Volume: 2022-08-25

Abstract: The Type III-E RNA-targeting effector complex (gRAMP/Cas7-11) is associated with a caspase-like protein (TPR-CHAT/Csx29) to form Craspase (CRISPR-guided caspase). Here we use cryo-electron microscopy snapshots of Craspase to explain its target RNA cleavage and protease activation mechanisms. Target-guide pairing extending into the 5′ region of the guide RNA displaces a gating loop in gRAMP, which triggers an extensive conformational relay that allosterically aligns the protease catalytic dyad and opens an amino acid sidechain-binding pocket. We further define Csx30 as the endogenous protein substrate that is site-specifically proteolyzed by RNA-activated Craspase. This protease activity is switched off by target RNA cleavage by gRAMP, and is not activated by RNA targets containing a matching protospacer flanking sequence. We thus conclude that Craspase is a target RNA-activated protease with self-regulatory capacity.

DOI: add5064

Source: https://www.science.org/doi/10.1126/science.add5064