1XHM

The Crystal Structure of a Biologically Active Peptide (SIGK) Bound to a G Protein Beta:Gamma Heterodimer


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.227 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and Molecular Characterization of a Preferred Protein Interaction Surface on G Protein betagamma Subunits.

Davis, T.L.Bonacci, T.M.Sprang, S.R.Smrcka, A.V.

(2005) Biochemistry 44: 10593-10604

  • DOI: 10.1021/bi050655i

  • PubMed Abstract: 
  • G protein betagamma subunits associate with many binding partners in cellular signaling cascades. In previous work, we used random-peptide phage display screening to identify a diverse family of peptides that bound to a common surface on Gbetagamma s ...

    G protein betagamma subunits associate with many binding partners in cellular signaling cascades. In previous work, we used random-peptide phage display screening to identify a diverse family of peptides that bound to a common surface on Gbetagamma subunits and blocked a subset of Gbetagamma effectors. Later studies showed that one of the peptides caused G protein activation through a novel Gbetagamma-dependent, nucleotide exchange-independent mechanism. Here we report the X-ray crystal structure of Gbeta(1)gamma(2) bound to this peptide, SIGK (SIGKAFKILGYPDYD), at 2.7 A resolution. SIGK forms a helical structure that binds the same face of Gbeta(1) as the switch II region of Galpha. The interaction interface can be subdivided into polar and nonpolar interfaces that together contain a mixture of binding determinants that may be responsible for the ability of this surface to recognize multiple protein partners. Systematic mutagenic analysis of the peptide-Gbeta(1) interface indicates that distinct sets of amino acids within this interface are required for binding of different peptides. Among these unique amino acid interactions, specific electrostatic binding contacts within the polar interface are required for peptide-mediated subunit dissociation. The data provide a mechanistic basis for multiple target recognition by Gbetagamma subunits with diverse functional interactions within a common interface and suggest that pharmacological targeting of distinct regions within this interface could allow for selective manipulation of Gbetagamma-dependent signaling pathways.


    Related Citations: 
    • Molecular Determinants on G Protein Beta:Gamma Subunits Responsible for Multiple Target Recognition and Nucleotide Exchange Independent Subunit Dissociation
      Bonacci, T.M.,Davis, T.L.,Sprang, S.R.,Smrcka, A.V.
      () TO BE PUBLISHED --: --


    Organizational Affiliation

    Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, MC 9050, Dallas, Texas 75390-9050, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Guanine nucleotide-binding protein G(I)/G(S)/G(T) beta subunit 1
A
340Bos taurusMutation(s): 0 
Gene Names: GNB1
Find proteins for P62871 (Bos taurus)
Go to Gene View: GNB1
Go to UniProtKB:  P62871
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Guanine nucleotide-binding protein G(I)/G(S)/G(O) gamma-2 subunit
B
77Bos taurusMutation(s): 0 
Gene Names: GNG2
Find proteins for P63212 (Bos taurus)
Go to Gene View: GNG2
Go to UniProtKB:  P63212
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
SIGK Peptide
C
15N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.227 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 45.468α = 90.00
b = 74.669β = 90.00
c = 108.023γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
CNSrefinement
SCALEPACKdata scaling
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-08-09
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance