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Crystal structure of Cmr2 suggests a nucleotide cyclase‐related enzyme in type III CRISPR‐Cas systems
Author(s) -
Zhu Xing,
Ye Keqiong
Publication year - 2012
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2012.02.036
Subject(s) - pyrococcus furiosus , trans activating crrna , crispr , biology , biochemistry , plasmid , chemistry , computational biology , genetics , dna , cas9 , gene , archaea
CRISPR RNAs (crRNAs) mediate sequence‐specific silencing of invading viruses and plasmids in prokaryotes. The crRNA–Cmr protein complex cleaves complementary RNA. We report the crystal structure of Pyrococcus furiosus Cmr2 (Cas10), a component of this Cmr complex and the signature protein in type III CRISPR systems. The structure reveals a nucleotide cyclase domain with a set of conserved catalytic residues that associates with an unexpected deviant cyclase domain like dimeric cyclases. Additionally, two helical domains resemble the thumb domain of A‐family DNA polymerase and Cmr5, respectively. Our results suggest that Cmr2 possesses novel enzymatic activity that remains to be elucidated.