5WPA

Structure of human SFPQ/PSPC1 heterodimer


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.29 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.219 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystal structure of a SFPQ/PSPC1 heterodimer provides insights into preferential heterodimerization of human DBHS family proteins.

Huang, J.Casas Garcia, G.P.Perugini, M.A.Fox, A.H.Bond, C.S.Lee, M.

(2018) J. Biol. Chem. 293: 6593-6602

  • DOI: 10.1074/jbc.RA117.001451

  • PubMed Abstract: 
  • Members of the Drosophila Behavior Human Splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS dom ...

    Members of the Drosophila Behavior Human Splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS domain provides a dimerization platform that is critical for the structural integrity and function of these proteins. The three human DBHS proteins - splicing factor proline- and glutamine-rich (SFPQ), paraspeckle component 1 (PSPC1), and non-POU domain-containing octamer binding protein (NONO) - form either homo- or heterodimers; however, the relative affinity and mechanistic details of preferential heterodimerization are yet to be deciphered. Here we report the crystal structure of a SFPQ/PSPC1 heterodimer to 2.3 Å resolution and analyzed the subtle structural differences between the SFPQ/PSPC1 heterodimer and the previously characterized SFPQ homodimer. Analytical ultracentrifugation to estimate the dimerization equilibrium of the SFPQ-containing dimers revealed that the SFPQ-containing dimers dissociate at low micromolar concentrations and that the heterodimers have higher affinities than the homodimer. Moreover, we observed that the apparent dissociation constant for the SFPQ/PSPC1 heterodimer was over six-fold lower than that of the SPFQ/NONO heterodimer. We propose that these differences in dimerization affinity may represent a potential mechanism by which PSPC1 at a lower relative cellular abundance can outcompete NONO to heterodimerize with SFPQ.


    Organizational Affiliation

    La Trobe University, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Splicing factor, proline- and glutamine-rich
A
261Homo sapiensMutation(s): 0 
Gene Names: SFPQ (PSF)
Find proteins for P23246 (Homo sapiens)
Go to Gene View: SFPQ
Go to UniProtKB:  P23246
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Paraspeckle component 1
B
261Homo sapiensMutation(s): 0 
Gene Names: PSPC1 (PSP1)
Find proteins for Q8WXF1 (Homo sapiens)
Go to Gene View: PSPC1
Go to UniProtKB:  Q8WXF1
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.29 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.219 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 89.229α = 90.00
b = 67.841β = 95.06
c = 92.204γ = 90.00
Software Package:
Software NamePurpose
Aimlessdata scaling
BUSTERrefinement
XDSdata reduction
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data

  • Deposited Date: 2017-08-04 
  • Released Date: 2018-03-21 
  • Deposition Author(s): Lee, M.

Funding OrganizationLocationGrant Number
Australian Research Council (ARC)Australia--

Revision History 

  • Version 1.0: 2018-03-21
    Type: Initial release
  • Version 1.1: 2018-03-28
    Type: Data collection, Database references
  • Version 1.2: 2018-05-09
    Type: Data collection, Database references
  • Version 1.3: 2020-01-01
    Type: Author supporting evidence