Year: 2011
Type: article
Abstract: The CRISPR system is a prokaryotic immune system that depends on the Cascade protein complex and small guide RNAs (crRNAs). The Cascade complex, loaded with crRNA, is now characterized, the overall architecture of Cascade deduced, and the complex found to identify targets by formation of an R loop between the crRNA and dsDNA. The CRISPR (clustered regularly interspaced short palindromic repeats) immune system in prokaryotes uses small guide RNAs to neutralize invading viruses and plasmids. In Escherichia coli, immunity depends on a ribonucleoprotein complex called Cascade. Here we present the composition and low-resolution structure of Cascade and show how it recognizes double-stranded DNA (dsDNA) targets in a sequence-specific manner. Cascade is a 405-kDa complex comprising five functionally essential CRISPR-associated (Cas) proteins (CasA1B2C6D1E1) and a 61-nucleotide CRISPR RNA (crRNA) with 5′-hydroxyl and 2′,3′-cyclic phosphate termini. The crRNA guides Cascade to dsDNA target sequences by forming base pairs with the complementary DNA strand while displacing the noncomplementary strand to form an R-loop. Cascade recognizes target DNA without consuming ATP, which suggests that continuous invader DNA surveillance takes place without energy investment. The structure of Cascade shows an unusual seahorse shape that undergoes conformational changes when it binds target DNA.
DOI: 10.1038/nsmb.2019
Authors: Matthijs M Jore, Magnus Lundgren, Esther van Duijn, Jelle B Bultema, Edze R Westra, Sakharam P Waghmare, Blake Wiedenheft, Ümit Pul, Reinhild Wurm, Rolf Wagner, Marieke R Beijer, Arjan Barendregt, Kaihong Zhou, Ambrosius P L Snijders, Mark J Dickman, Jennifer A Doudna, Egbert J Boekema, Albert J R Heck, John van der Oost, Stan J J Brouns
Institutions: Wageningen University & Research, Uppsala University, Imperial College London, Utrecht University, Netherlands Proteomics Centre, University of Groningen, University of Sheffield, Howard Hughes Medical Institute, Lawrence Berkeley National Laboratory, University of California, Berkeley, Heinrich Heine University Düsseldorf
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $12,690
Funders: Howard Hughes Medical Institute, Life Sciences Research Foundation, Research Councils UK, Deutsche Forschungsgemeinschaft, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Directorate for Biological Sciences, Engineering and Physical Sciences Research Council, Biotechnology and Biological Sciences Research Council
OpenAlex ID: W2062008243