Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 80.74 kDa 
• Atom Count: 5206 
• Modelled Residue Count: 592 
• Deposited Residue Count: 626 
• Unique protein chains: 1
• Unique nucleic acid chains: 1

4ILL

Recognition and Cleavage of a non-structured CRISPR RNA by its Processing Endoribonuclease Cas6

• DOI: 10.2210/pdb4ILL/pdb
• NDB: NA2203

• Classification: HYDROLASE/RNA
• Organism(s): Saccharolobus solfataricus P2
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2012-12-31 Released: 2013-03-20 
• Deposition Author(s): Shao, Y., Li, H.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.48 Å
• R-Value Free: 0.239 
• R-Value Work: 0.204 
• R-Value Observed: 0.207 

Literature

Recognition and cleavage of a nonstructured CRISPR RNA by its processing endoribonuclease Cas6.

Shao, Y., Li, H.

(2013) Structure 21: 385-393

• PubMed: 23454186 
• DOI: 10.1016/j.str.2013.01.010
• Primary Citation of Related Structures:  
  4ILR, 4ILL, 4ILM


• PubMed Abstract: 
  

Clustered regularly interspaced short palindromic repeats (CRISPRs) confer adaptive immunity to prokaryotes through a small RNA-mediated mechanism. Specific endoribonucleases are required by all CRISPR-bearing organisms to process CRISPR RNAs into small RNA that serve as guides for defensive effector complexes. The molecular mechanism of how the endoribonucleases process the class of CRISPR RNA containing no predicted secondary structural features remains largely elusive. Here, we report cocrystal structures of a processing endoribonuclease bound with a noncleavable RNA substrate and its product-like fragment derived from a nonpalindramic repeat. The enzyme stabilizes a short RNA stem-loop structure near the cleavage site and cleaves the phosphodiester bond using an active site comprised of arginine and lysine residues. The distinct RNA binding and cleavage mechanisms underline the diversity in CRISPR RNA processing.

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Organizational Affiliation: 

Institute of Molecular Biophysics, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CRISPR-associated endoribonuclease Cas6 2	A, C [auth B]	289	Saccharolobus solfataricus P2	Mutation(s): 0  Gene Names: cas6b, SSO2004 EC: 3.1
Find proteins for Q97WV8 (Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)) Explore Q97WV8  Go to UniProtKB:  Q97WV8

Entity ID: 2
Molecule	Chains	Length	Organism	Image
RNA (5'-R(*GP*CP*UP*AP*AP*UP*CP*UP*AP*CP*UP*AP*UP*AP*GP*AP*AP*UP*UP*GP*AP*AP*AP*G)-3')	B [auth R], D [auth C]	24	N/A

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.48 Å
• R-Value Free: 0.239 
• R-Value Work: 0.204 
• R-Value Observed: 0.207 
• Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 159.735	α = 90
b = 68.542	β = 119.12
c = 79.831	γ = 90

Software Package:

Software Name	Purpose
HKL-2000	data collection
PHASES	phasing
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2012-12-31 
• Released Date: 2013-03-20 
Deposition Author(s): Shao, Y., Li, H.

Revision History  

• Version 1.0: 2013-03-20
  Type: Initial release
  
• Version 1.1: 2013-05-01
  Changes: Database references