Biological Assembly 1  

 3D View: Structure | 1D-3D View | Validation Report | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 40.83 kDa 
• Atom Count: 2649 
• Modelled Residue Count: 310 
• Deposited Residue Count: 353 
• Unique protein chains: 1

1GIA

STRUCTURE OF ACTIVE CONFORMATIONS OF GIA1 AND THE MECHANISM OF GTP HYDROLYSIS

• PDB DOI: 10.2210/pdb1GIA/pdb

• Classification: SIGNAL TRANSDUCTION PROTEIN
• Organism(s): Rattus norvegicus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1994-07-20 Released: 1994-09-30 
• Deposition Author(s): Berghuis, A.M., Coleman, D.E., Sprang, S.R.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.228 
• R-Value Work: 0.175 
• R-Value Observed: 0.175 

Literature

Structures of active conformations of Gi alpha 1 and the mechanism of GTP hydrolysis.

Coleman, D.E., Berghuis, A.M., Lee, E., Linder, M.E., Gilman, A.G., Sprang, S.R.

(1994) Science 265: 1405-1412

• PubMed: 8073283 
• DOI: 10.1126/science.8073283
• Primary Citation of Related Structures:  
  1GFI, 1GIA, 1GIL


• PubMed Abstract: 
  

Mechanisms of guanosine triphosphate (GTP) hydrolysis by members of the G protein alpha subunit-p21ras superfamily of guanosine triphosphatases have been studied extensively but have not been well understood. High-resolution x-ray structures of the GTP gamma S and GDP.AlF4- complexes formed by the G protein Gi alpha 1 demonstrate specific roles in transition-state stabilization for two highly conserved residues. Glutamine204 (Gln61 in p21ras) stabilizes and orients the hydrolytic water in the trigonal-bipyramidal transition state. Arginine 178 stabilizes the negative charge at the equatorial oxygen atoms of the pentacoordinate phosphate intermediate. Conserved only in the G alpha family, this residue may account for the higher hydrolytic rate of G alpha proteins relative to those of the p21ras family members. The fold of Gi alpha 1 differs from that of the homologous Gt alpha subunit in the conformation of a helix-loop sequence located in the alpha-helical domain that is characteristic of these proteins; this site may participate in effector binding. The amino-terminal 33 residues are disordered in GTP gamma S-Gi alpha 1, suggesting a mechanism that may promote release of the beta gamma subunit complex when the alpha subunit is activated by GTP.

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Related Citations: 

• Crystallization and Preliminary Crystallographic Studies of Gia1 and Mutants of Gia1 in the GTP and Gdp-Bound States
  Coleman, D.E., Lee, E., Mixon, M.B., Linder, M.E., Berghuis, A.M., Gilman, A.G., Sprang, S.R.
  (1994) J Mol Biol 238: 630

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Organizational Affiliation: 

Howard Hughes Medical Institute, Dallas, TX.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
G PROTEIN GI ALPHA 1	A	353	Rattus norvegicus	Mutation(s): 0  Gene Names: Gnai1, Gnai-1
UniProt
Find proteins for P10824 (Rattus norvegicus) Explore P10824  Go to UniProtKB:  P10824

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
GSP	C [auth A]	5'-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE C10 H16 N5 O13 P3 S XOFLBQFBSOEHOG-UUOKFMHZSA-N
MG	B [auth A]	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.228 
• R-Value Work: 0.175 
• R-Value Observed: 0.175 
• Space Group: P 3₂ 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 80.6	α = 90
b = 80.6	β = 90
c = 106.5	γ = 120

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	refinement
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1994-07-20 
• Released Date: 1994-09-30 
Deposition Author(s): Berghuis, A.M., Coleman, D.E., Sprang, S.R.

Revision History  

• Version 1.0: 1994-09-30
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance