Crystal structure of PCI domain from A. thaliana COP9 signalosome subunit 7 (CSN7)

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.166 

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The Arabidopsis COP9 signalosome subunit 7 is a model PCI domain protein with subdomains involved in COP9 signalosome assembly

Dessau, M.Halimi, Y.Erez, T.Chomsky-Hecht, O.Chamovitz, D.A.Hirsch, J.A.

(2008) Plant Cell 20: 2815-2834

  • DOI: https://doi.org/10.1105/tpc.107.053801
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The COP9 Signalosome (CSN) is a multiprotein complex that was originally identified in Arabidopsis thaliana as a negative regulator of photomorphogenesis and subsequently shown to be a general eukaryotic regulator of developmental signaling. The CSN plays various roles, but it has been most often implicated in regulating protein degradation pathways. Six of eight CSN subunits bear a sequence motif called PCI. Here, we report studies of subunit 7 (CSN7) from Arabidopsis, which contains such a motif. Our in vitro and structural results, based on 1.5 A crystallographic data, enable a definition of a PCI domain, built from helical bundle and winged helix subdomains. Using functional binding assays, we demonstrate that the PCI domain (residues 1 to 169) interacts with two other PCI proteins, CSN8 and CSN1. CSN7 interactions with CSN8 use both PCI subdomains. Furthermore, we show that a C-terminal tail outside of this PCI domain is responsible for association with the non-PCI subunit, CSN6. In vivo studies of transgenic plants revealed that the overexpressed CSN7 PCI domain does not assemble into the CSN, nor can it complement a null mutation of CSN7. However, a CSN7 clone that contains the PCI domain plus part of the CSN6 binding domain can complement the null mutation in terms of seedling viability and photomorphogenesis. These transgenic plants, though, are defective in adult growth, suggesting that the CSN7 C-terminal tail plays additional functional roles. Together, the findings have implications for CSN assembly and function, highlighting necessary interactions between subunits.

  • Organizational Affiliation

    Department of Biochemistry, Daniella Rich Institute for Structural Biology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
COP9 signalosome complex subunit 7169Arabidopsis thalianaMutation(s): 0 
Gene Names: FUS5CSN7At1g02090T7I23.24T7I23.25
Find proteins for Q94JU3 (Arabidopsis thaliana)
Explore Q94JU3 
Go to UniProtKB:  Q94JU3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ94JU3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.166 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.094α = 90
b = 85.796β = 90
c = 72.343γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-10-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance