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Structure and Activity of the RNA-Targeting Type III-B CRISPR-Cas Complex of Thermus thermophilus.
- Source :
-
Molecular Cell . Oct2013, Vol. 52 Issue 1, p135-145. 11p. - Publication Year :
- 2013
-
Abstract
- Summary: The CRISPR-Cas system is a prokaryotic host defense system against genetic elements. The Type III-B CRISPR-Cas system of the bacterium Thermus thermophilus, the TtCmr complex, is composed of six different protein subunits (Cmr1-6) and one crRNA with a stoichiometry of Cmr112131445361:crRNA1. The TtCmr complex copurifies with crRNA species of 40 and 46 nt, originating from a distinct subset of CRISPR loci and spacers. The TtCmr complex cleaves the target RNA at multiple sites with 6 nt intervals via a 5′ ruler mechanism. Electron microscopy revealed that the structure of TtCmr resembles a “sea worm” and is composed of a Cmr2-3 heterodimer “tail,” a helical backbone of Cmr4 subunits capped by Cmr5 subunits, and a curled “head” containing Cmr1 and Cmr6. Despite having a backbone of only four Cmr4 subunits and being both longer and narrower, the overall architecture of TtCmr resembles that of Type I Cascade complexes. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 10972765
- Volume :
- 52
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Molecular Cell
- Publication Type :
- Academic Journal
- Accession number :
- 90630183
- Full Text :
- https://doi.org/10.1016/j.molcel.2013.09.013