Structure of the Saccharolobus solfataricus type III-D CRISPR effector

Cannone, G., Kompaniiets, D., Graham, S., White, M. F. and Spagnolo, L. (2023) Structure of the Saccharolobus solfataricus type III-D CRISPR effector. Current Research in Structural Biology, 5, 100098. (doi: 10.1016/j.crstbi.2023.100098) (PMID:36843655) (PMCID:PMC9945777)

Abstract

CRISPR-Cas is a prokaryotic adaptive immune system, classified into six different types, each characterised by a signature protein. Type III systems, classified based on the presence of a Cas10 subunit, are rather diverse multi-subunit assemblies with a range of enzymatic activities and downstream ancillary effectors. The broad array of current biotechnological CRISPR applications is mainly based on proteins classified as Type II, however recent developments established the feasibility and efficacy of multi-protein Type III CRISPR-Cas effector complexes as RNA-targeting tools in eukaryotes. The crenarchaeon Saccharolobus solfataricus has two type III system subtypes (III–B and III-D). Here, we report the cryo-EM structure of the Csm Type III-D complex from S. solfataricus (SsoCsm), which uses CRISPR RNA to bind target RNA molecules, activating the Cas10 subunit for antiviral defence. The structure reveals the complex organisation, subunit/subunit connectivity and protein/guide RNA interactions of the SsoCsm complex, one of the largest CRISPR effectors known.

• Item Type: Articles
• Additional Information: We acknowledge funding from BBSRC BB/J005673/1 project grant to LS and MFW and ERC funding to MFW (grant ref 101018608). DK was funded by a Darwin Trust of Edinburgh grant. We acknowledge Diamond Light Source for access and support of the cryo-EM facilities at the UK's national Electron Bio-imaging Centre (eBIC) under proposal EM16637-14, funded by the Wellcome Trust, MRC and BBRSC. The Scottish Centre for Macromolecular Imaging (SCMI) is funded by the MRC (MC_PC_17135) and SFC (H17007).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cannone, Dr Giuseppe and Kompaniiets, Dmytro and Spagnolo, Dr Laura
• Authors: Cannone, G., Kompaniiets, D., Graham, S., White, M. F., and Spagnolo, L.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Current Research in Structural Biology
• Publisher: Elsevier
• ISSN: 2665-928X
• ISSN (Online): 2665-928X
• Published Online: 10 February 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Current Research in Structural Biology
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
301445		The Scottish Macromolecular Imaging Centre (SMIC)	David Bhella	Medical Research Council (MRC)	MC_PC_17135	III - Centre for Virus Research
301474		The purchase and maintenance of a cryo-electron microscope	David Bhella	Scottish Funding Council (SFC)	H17007	III - Centre for Virus Research