Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 40806.25 
• Atom Count: 2554 
• Residue Count: 353 
• Unique protein chains: 1

1SVK

Structure of the K180P mutant of Gi alpha subunit bound to AlF4 and GDP

• DOI: 10.2210/pdb1SVK/pdb

• Classification: HYDROLASE SIGNALING PROTEIN
• Organism(s): Rattus norvegicus
• Expression System: Escherichia coli
• Mutation(s): 1 


• Deposited: 2004-03-29 Released: 2004-06-01 
• Deposition Author(s): Thomas, C.J., Du, X., Li, P., Wang, Y., Ross, E.M., Sprang, S.R.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2 Å
• R-Value Free: 0.239 
• R-Value Work: 0.197 

Literature

Uncoupling conformational change from GTP hydrolysis in a heterotrimeric G protein {alpha}-subunit.

Thomas, C.J., Du, X., Li, P., Wang, Y., Ross, E.M., Sprang, S.R.

(2004) Proc.Natl.Acad.Sci.USA 101: 7560-7565

• PubMed: 15128951 
• DOI: 10.1073/pnas.0304091101
• Primary Citation of Related Structures:  
  1SVS


• PubMed Abstract: 
  

Heterotrimeric G protein alpha (G alpha) subunits possess intrinsic GTPase activity that leads to functional deactivation with a rate constant of approximately 2 min(-1) at 30 degrees C. GTP hydrolysis causes conformational changes in three regions of G alpha, including Switch I and Switch II. Mutation of G202-->A in Switch II of G alpha(i1) accelerates the rates of both GTP hydrolysis and conformational change, which is measured by the loss of fluorescence from Trp-211 in Switch II. Mutation of K180-->P in Switch I increases the rate of conformational change but decreases the GTPase rate, which causes transient but substantial accumulation of a low-fluorescence G alpha(i1).GTP species. Isothermal titration calorimetric analysis of the binding of (G202A)G alpha(i1) and (K180P)G alpha(i1) to the GTPase-activating protein RGS4 indicates that the G202A mutation stabilizes the pretransition state-like conformation of G alpha(i1) that is mimicked by the complex of G alpha(i1) with GDP and magnesium fluoroaluminate, whereas the K180P mutation destabilizes this state. The crystal structures of (K180P)G alpha(i1) bound to a slowly hydrolyzable GTP analog, and the GDP.magnesium fluoroaluminate complex provide evidence that the Mg(2+) binding site is destabilized and that Switch I is torsionally restrained by the K180P mutation. The data are consistent with a catalytic mechanism for G alpha in which major conformational transitions in Switch I and Switch II are obligate events that precede the bond-breaking step in GTP hydrolysis. In (K180P)G alpha(i1), the two events are decoupled kinetically, whereas in the native protein they are concerted.

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Organizational Affiliation: 

Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9050, USA.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Guanine nucleotide-binding protein G(i), alpha-1 subunit	A	353	Rattus norvegicus	Mutation(s): 1  Gene Names: Gnai1 (Gnai-1)
Find proteins for P10824 (Rattus norvegicus) Go to UniProtKB:  P10824

Small Molecules

Ligands 3 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
GDP	A	GUANOSINE-5'-DIPHOSPHATE C10 H15 N5 O11 P2 QGWNDRXFNXRZMB-UUOKFMHZSA-N
ALF	A	TETRAFLUOROALUMINATE ION Al F4 UYOMQIYKOOHAMK-UHFFFAOYSA-J
MG	A	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2 Å
• R-Value Free: 0.239 
• R-Value Work: 0.197 
• Space Group: P 3₂ 2 1

Unit Cell:

Length (Å)	Angle (°)
a = 79.473	α = 90.00
b = 79.473	β = 90.00
c = 105.209	γ = 120.00

Software Package:

Software Name	Purpose
CNS	refinement
HKL-2000	data reduction
SCALEPACK	data scaling
CNS	phasing
HKL-2000	data collection

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-03-29 
• Released Date: 2004-06-01 
• Deposition Author(s): Thomas, C.J., Du, X., Li, P., Wang, Y., Ross, E.M., Sprang, S.R.

Revision History 

• Version 1.0: 2004-06-01
  Type: Initial release
• Version 1.1: 2008-04-30
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance