8Q42

Crystal structure of cA4-bound Can2 (E341A) in complex with oligo-A DNA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.97 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.188 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Substrate selectivity and catalytic activation of the type III CRISPR ancillary nuclease Can2.

Jungfer, K.Sigg, A.Jinek, M.

(2024) Nucleic Acids Res 52: 462-473

  • DOI: https://doi.org/10.1093/nar/gkad1102
  • Primary Citation of Related Structures:  
    8Q3Y, 8Q3Z, 8Q40, 8Q41, 8Q42, 8Q43, 8Q44

  • PubMed Abstract: 

    Type III CRISPR-Cas systems provide adaptive immunity against foreign mobile genetic elements through RNA-guided interference. Sequence-specific recognition of RNA targets by the type III effector complex triggers the generation of cyclic oligoadenylate (cOA) second messengers that activate ancillary effector proteins, thus reinforcing the host immune response. The ancillary nuclease Can2 is activated by cyclic tetra-AMP (cA4); however, the mechanisms underlying cA4-mediated activation and substrate selectivity remain elusive. Here we report crystal structures of Thermoanaerobacter brockii Can2 (TbrCan2) in substrate- and product-bound complexes. We show that TbrCan2 is a single strand-selective DNase and RNase that binds substrates via a conserved SxTTS active site motif, and reveal molecular interactions underpinning its sequence preference for CA dinucleotides. Furthermore, we identify a molecular interaction relay linking the cA4 binding site and the nuclease catalytic site to enable divalent metal cation coordination and catalytic activation. These findings provide key insights into the molecular mechanisms of Can2 nucleases in type III CRISPR-Cas immunity and may guide their technological development for nucleic acid detection applications.


  • Organizational Affiliation

    Department of Biochemistry, University of Zurich, Zurich, Switzerland.


Macromolecules

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DUF1887 family protein
A, B
439Thermoanaerobacter brockii subsp. finnii Ako-1Mutation(s): 1 
Gene Names: Thebr_0943
UniProt
Find proteins for E8URK0 (Thermoanaerobacter brockii subsp. finnii (strain ATCC 43586 / DSM 3389 / AKO-1))
Explore E8URK0 
Go to UniProtKB:  E8URK0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE8URK0
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains LengthOrganismImage
DNA (5'-D(*AP*AP*AP*A)-3')C [auth D]6Thermoanaerobacter brockii subsp. finnii Ako-1
Sequence Annotations
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  • Reference Sequence

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Entity ID: 3
MoleculeChains LengthOrganismImage
Cyclic tetraadenosine monophosphate (cA4)D [auth X]4synthetic construct
Sequence Annotations
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  • Reference Sequence
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.97 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.188 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.897α = 90
b = 78.026β = 95.45
c = 94.791γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
autoPROCdata scaling
XDSdata reduction
Cootmodel building
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
European Research Council (ERC)European UnionERC-CoG-820152

Revision History  (Full details and data files)

  • Version 1.0: 2023-11-22
    Type: Initial release
  • Version 1.1: 2023-12-13
    Changes: Database references
  • Version 1.2: 2024-01-24
    Changes: Database references