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Mol Cell. 2012 Feb 10;45(3):303-13. doi: 10.1016/j.molcel.2011.12.013. Epub 2012 Jan 5.

Structure and mechanism of the CMR complex for CRISPR-mediated antiviral immunity.

Author information

1
Biomedical Sciences Research Complex, University of St Andrews, Fife KY16 9ST, UK.

Abstract

The prokaryotic clusters of regularly interspaced palindromic repeats (CRISPR) system utilizes genomically encoded CRISPR RNA (crRNA), derived from invading viruses and incorporated into ribonucleoprotein complexes with CRISPR-associated (CAS) proteins, to target and degrade viral DNA or RNA on subsequent infection. RNA is targeted by the CMR complex. In Sulfolobus solfataricus, this complex is composed of seven CAS protein subunits (Cmr1-7) and carries a diverse "payload" of targeting crRNA. The crystal structure of Cmr7 and low-resolution structure of the complex are presented. S. solfataricus CMR cleaves RNA targets in an endonucleolytic reaction at UA dinucleotides. This activity is dependent on the 8 nt repeat-derived 5' sequence in the crRNA, but not on the presence of a protospacer-associated motif (PAM) in the target. Both target and guide RNAs can be cleaved, although a single molecule of guide RNA can support the degradation of multiple targets.

PMID:
22227115
PMCID:
PMC3381847
DOI:
10.1016/j.molcel.2011.12.013
[Indexed for MEDLINE]
Free PMC Article

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