TY - JOUR
T1 - Crystal structure of the largest subunit of a bacterial RNA-guided immune complex and its role in DNA target binding
AU - Mulepati, Sabin
AU - Orr, Amberly
AU - Bailey, Scott
PY - 2012/6/29
Y1 - 2012/6/29
N2 - Prokaryotes make use of small RNAs encoded by CRISPR (clustered regularly interspaced short palindromic repeat) loci to provide immunity against bacteriophage or plasmid invasion. In Escherichia coli, the CRISPR-associated complex for antiviral defense (Cascade) utilizes these RNAs to target foreignDNAfor destruction. CasA, the largest subunit of Cascade, is essential for its function. Here we report the crystal structure of Thermus thermophilus CasA. The structure is composed of two domains that are arranged in a chair-like conformation with a novel fold forming the larger N-terminal domain. Docking of the crystal structure into cryo-electron microscopy maps reveals two loops in CasA that likely have important functions in DNA target binding. Finally, DNA binding experiments show that CasA is essential for binding of Cascade to DNA target.
AB - Prokaryotes make use of small RNAs encoded by CRISPR (clustered regularly interspaced short palindromic repeat) loci to provide immunity against bacteriophage or plasmid invasion. In Escherichia coli, the CRISPR-associated complex for antiviral defense (Cascade) utilizes these RNAs to target foreignDNAfor destruction. CasA, the largest subunit of Cascade, is essential for its function. Here we report the crystal structure of Thermus thermophilus CasA. The structure is composed of two domains that are arranged in a chair-like conformation with a novel fold forming the larger N-terminal domain. Docking of the crystal structure into cryo-electron microscopy maps reveals two loops in CasA that likely have important functions in DNA target binding. Finally, DNA binding experiments show that CasA is essential for binding of Cascade to DNA target.
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U2 - 10.1074/jbc.C112.379503
DO - 10.1074/jbc.C112.379503
M3 - Article
C2 - 22621933
AN - SCOPUS:84863329741
VL - 287
SP - 22445
EP - 22449
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 27
ER -