Crystal structure of IBV X-domain at pH 8.5

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.171 

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This is version 1.3 of the entry. See complete history


Crystal structures of the X-domains of a Group-1 and a Group-3 coronavirus reveal that ADP-ribose-binding may not be a conserved property.

Piotrowski, Y.Hansen, G.Boomaars-van der Zanden, A.L.Snijder, E.J.Gorbalenya, A.E.Hilgenfeld, R.

(2009) Protein Sci 18: 6-16

  • DOI: https://doi.org/10.1002/pro.15
  • Primary Citation of Related Structures:  
    3EJF, 3EJG, 3EKE

  • PubMed Abstract: 

    The polyproteins of coronaviruses are cleaved by viral proteases into at least 15 nonstructural proteins (Nsps). Consisting of five domains, Nsp3 is the largest of these (180-210 kDa). Among these domains, the so-called X-domain is believed to act as ADP-ribose-1''-phosphate phosphatase or to bind poly(ADP-ribose). However, here we show that the X-domain of Infectious Bronchitis Virus (strain Beaudette), a Group-3 coronavirus, fails to bind ADP-ribose. This is explained on the basis of the crystal structure of the protein, determined at two different pH values. For comparison, we also describe the crystal structure of the homologous X-domain from Human Coronavirus 229E, a Group-1 coronavirus, which does bind ADP-ribose.

  • Organizational Affiliation

    Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Non-structural protein 3176Infectious bronchitis virusMutation(s): 0 
Gene Names: 1a
EC: 3.4.22
Find proteins for P0C6Y1 (Avian infectious bronchitis virus (strain Beaudette))
Explore P0C6Y1 
Go to UniProtKB:  P0C6Y1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0C6Y1
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.171 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.207α = 90
b = 79.811β = 90
c = 99.741γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-09-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description
  • Version 1.3: 2024-02-21
    Changes: Data collection, Database references