6NJY

Type IV CRISPR associated RNA endonuclease Cas6 - apo form

Summary for 6NJY

• Entry DOI: 10.2210/pdb6njy/pdb
• Descriptor: Type IV CRISPR associated Cas6 RNA endonuclease, SULFATE ION, beta-D-glucopyranose, ... (4 entities in total)
• Functional Keywords: crispr, cas, nuclease, rna, cas6, csf5, rna binding protein
• Biological source: Mahella australiensis (strain DSM 15567 / CIP 107919 / 50-1 BON)
• Total number of polymer chains: 2
• Total formula weight: 59103.36

Authors

Jackson, R.N.,Warner, E.,Olsen, K.J. (deposition date: 2019-01-04, release date: 2019-07-10, Last modification date: 2024-03-13)

Primary citation

Taylor, H.N.,Warner, E.E.,Armbrust, M.J.,Crowley, V.M.,Olsen, K.J.,Jackson, R.N.
Structural basis of Type IV CRISPR RNA biogenesis by a Cas6 endoribonuclease.
Rna Biol., 16:1438-1447, 2019

PubMed Abstract: Prokaryotic CRISPR-Cas adaptive immune systems rely on small non-coding RNAs derived from CRISPR loci to recognize and destroy complementary nucleic acids. However, the mechanism of Type IV CRISPR RNA (crRNA) biogenesis is poorly understood. To dissect the mechanism of Type IV CRISPR RNA biogenesis, we determined the x-ray crystal structure of the putative Type IV CRISPR associated endoribonuclease Cas6 from ( Cas6-IV) and characterized its enzymatic activity with RNA cleavage assays. We show that Cas6-IV specifically cleaves Type IV crRNA repeats at the 3' side of a predicted stem loop, with a metal-independent, single-turnover mechanism that relies on a histidine and a tyrosine located within the putative endonuclease active site. Structure and sequence alignments with Cas6 orthologs reveal that although Cas6-IV shares little sequence homology with other Cas6 proteins, all share common structural features that bind distinct crRNA repeat sequences. This analysis of Type IV crRNA biogenesis provides a structural and biochemical framework for understanding the similarities and differences of crRNA biogenesis across multi-subunit Class 1 CRISPR immune systems.

PubMed: 31232162
DOI: 10.1080/15476286.2019.1634965

Experimental method

X-RAY DIFFRACTION (1.76 Å)