8TL0

Structure of activated SAVED-CHAT filament

Summary for 8TL0

• Entry DOI: 10.2210/pdb8tl0/pdb
• EMDB information: 41358
• Descriptor: CHAT domain-containing protein, RNA (5'-R(*AP*AP*A)-3') (2 entities in total)
• Functional Keywords: saved-chat, immune system
• Biological source: Haliangium ochraceum; More
• Total number of polymer chains: 14
• Total formula weight: 387246.94

Authors

Bravo, J.P.K.,Taylor, D.W. (deposition date: 2023-07-26, release date: 2024-03-06, Last modification date: 2025-05-14)

Primary citation

Steens, J.A.,Bravo, J.P.K.,Salazar, C.R.P.,Yildiz, C.,Amieiro, A.M.,Kostlbacher, S.,Prinsen, S.H.P.,Andres, A.S.,Patinios, C.,Bardis, A.,Barendregt, A.,Scheltema, R.A.,Ettema, T.J.G.,van der Oost, J.,Taylor, D.W.,Staals, R.H.J.
Type III-B CRISPR-Cas cascade of proteolytic cleavages.
Science, 383:512-519, 2024

PubMed Abstract: The generation of cyclic oligoadenylates and subsequent allosteric activation of proteins that carry sensory domains is a distinctive feature of type III CRISPR-Cas systems. In this work, we characterize a set of associated genes of a type III-B system from that contains two caspase-like proteases, SAVED-CHAT and PCaspase (prokaryotic caspase), co-opted from a cyclic oligonucleotide-based antiphage signaling system (CBASS). Cyclic tri-adenosine monophosphate (AMP)-induced oligomerization of SAVED-CHAT activates proteolytic activity of the CHAT domains, which specifically cleave and activate PCaspase. Subsequently, activated PCaspase cleaves a multitude of proteins, which results in a strong interference phenotype in vivo in Taken together, our findings reveal how a CRISPR-Cas-based detection of a target RNA triggers a cascade of caspase-associated proteolytic activities.

PubMed: 38301007
DOI: 10.1126/science.adk0378

Experimental method

ELECTRON MICROSCOPY (3.1 Å)