Crystal structure of Cmr2 suggests a nucleotide cyclase-related enzyme in type III CRISPR-Cas systems

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• 作者：Xing Zhu^a ; ^b ; Keqiong Ye^b ; ^{yekeqiong@nibs.ac.cn}
• 关键词：CRISPR ; clustered regularly interspaced short palindromic repeat ; Cas ; CRISPR-associated ; crRNA ; CRISPR RNA ; NC ; nucleotide cyclase ; AC ; adenylate cyclase ; DGC ; diguanylate cyclase ; c-di-GMP ; bis-(3&prime ; &ndash ; 5&prime ; )-cyclic di-guanosine monophosphate
• 刊名：FEBS Letters
• 出版年：2012
• 出版时间：23 March, 2012
• 年：2012
• 卷：586
• 期：6
• 页码：939-945
• 全文大小：1584 K

文摘

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.