4Z7K

Crystal structure of CRISPR RNA processing endoribonuclease Cas6b

Summary for 4Z7K

• Entry DOI: 10.2210/pdb4z7k/pdb
• Related: 4Z7L
• Descriptor: Cas6b, RNA/DNA Hybrid (31-MER) (2 entities in total)
• Functional Keywords: cas6, endoribonuclease, crispr rna, hydrolase-rna-dna complex, hydrolase/rna/dna
• Biological source: Methanococcus maripaludis (strain C5 / ATCC BAA-1333); More
• Total number of polymer chains: 3
• Total formula weight: 61061.16

Authors

Li, H. (deposition date: 2015-04-07, release date: 2016-04-13, Last modification date: 2024-03-06)

Primary citation

Shao, Y.,Richter, H.,Sun, S.,Sharma, K.,Urlaub, H.,Randau, L.,Li, H.
A Non-Stem-Loop CRISPR RNA Is Processed by Dual Binding Cas6.
Structure, 24:547-554, 2016

PubMed Abstract: A subclass of recently discovered CRISPR repeat RNA in bacteria contains minimally recognizable structural features that facilitate an unknown mechanism of recognition and processing by the Cas6 family of endoribonucleases. Cocrystal structures of Cas6 from Methanococcus maripaludis (MmCas6b) bound with its repeat RNA revealed a dual site binding structure and a cleavage site conformation poised for phosphodiester bond breakage. Two non-interacting MmCas6b bind to two separate AAYAA motifs within the same repeat, one distal and one adjacent to the cleavage site. This bound structure potentially competes with a stable but non-productive RNA structure. At the cleavage site, MmCas6b supplies a base pair mimic to stabilize a short 2 base pair stem immediately upstream of the scissile phosphate. Complementary biochemical analyses support the dual-AAYAA binding model and a critical role of the protein-RNA base pair mimic. Our results reveal a previously unknown method of processing non-stem-loop CRISPR RNA by Cas6.

PubMed: 26996962
DOI: 10.1016/j.str.2016.02.009

Experimental method

X-RAY DIFFRACTION (3 Å)