2XTZ

Crystal structure of the G alpha protein AtGPA1 from Arabidopsis thaliana


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.34 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.212 

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This is version 1.5 of the entry. See complete history


Literature

The Crystal Structure of a Self-Activating G Protein Alpha Subunit Reveals its Distinct Mechanism of Signal Initiation

Jones, J.C.Duffy, J.W.Machius, M.Temple, B.R.S.Dohlman, H.G.Jones, A.M.

(2011) Sci Signal 159: RA8

  • DOI: https://doi.org/10.1126/scisignal.2001446
  • Primary Citation of Related Structures:  
    2XTZ

  • PubMed Abstract: 

    In animals, heterotrimeric guanine nucleotide-binding protein (G protein) signaling is initiated by G protein-coupled receptors (GPCRs), which activate G protein α subunits; however, the plant Arabidopsis thaliana lacks canonical GPCRs, and its G protein α subunit (AtGPA1) is self-activating. To investigate how AtGPA1 becomes activated, we determined its crystal structure. AtGPA1 is structurally similar to animal G protein α subunits, but our crystallographic and biophysical studies revealed that it had distinct properties. Notably, the helical domain of AtGPA1 displayed pronounced intrinsic disorder and a tendency to disengage from the Ras domain of the protein. Domain substitution experiments showed that the helical domain of AtGPA1 was necessary for self-activation and sufficient to confer self-activation to an animal G protein α subunit. These findings reveal the structural basis for a mechanism for G protein activation in Arabidopsis that is distinct from the well-established mechanism found in animals.


  • Organizational Affiliation

    Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
GUANINE NUCLEOTIDE-BINDING PROTEIN ALPHA-1 SUBUNIT
A, B, C
354Arabidopsis thalianaMutation(s): 0 
EC: 3.6.5.1
UniProt
Find proteins for P18064 (Arabidopsis thaliana)
Explore P18064 
Go to UniProtKB:  P18064
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP18064
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
GSP
Query on GSP

Download Ideal Coordinates CCD File 
E [auth A],
I [auth B],
N [auth C]
5'-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE
C10 H16 N5 O13 P3 S
XOFLBQFBSOEHOG-UUOKFMHZSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
G [auth A],
K [auth B],
O [auth C],
P [auth C],
Q [auth C]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
CL
Query on CL

Download Ideal Coordinates CCD File 
F [auth A],
J [auth B],
L [auth B],
R [auth C]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
MG
Query on MG

Download Ideal Coordinates CCD File 
D [auth A],
H [auth B],
M [auth C]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
CSS
Query on CSS
A, B, C
L-PEPTIDE LINKINGC3 H7 N O2 S2CYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.34 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.212 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.13α = 90
b = 119.347β = 90
c = 161.725γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-02-16
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-04-03
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.4: 2019-05-15
    Changes: Data collection, Experimental preparation
  • Version 1.5: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description