1SVK

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


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 U S A 101: 7560-7565

  • DOI: 10.1073/pnas.0304091101
  • Primary Citation of Related Structures:  
    1SVK, 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 ...

    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.


    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
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Guanine nucleotide-binding protein G(i), alpha-1 subunitA353Rattus norvegicusMutation(s): 1 
Gene Names: Gnai1Gnai-1
EC: 3.6.1.46
UniProt
Find proteins for P10824 (Rattus norvegicus)
Explore P10824 
Go to UniProtKB:  P10824
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP10824
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GDP
Query on GDP

Download Ideal Coordinates CCD File 
D [auth A]GUANOSINE-5'-DIPHOSPHATE
C10 H15 N5 O11 P2
QGWNDRXFNXRZMB-UUOKFMHZSA-N
 Ligand Interaction
ALF
Query on ALF

Download Ideal Coordinates CCD File 
C [auth A]TETRAFLUOROALUMINATE ION
Al F4
UYOMQIYKOOHAMK-UHFFFAOYSA-J
 Ligand Interaction
MG
Query on MG

Download Ideal Coordinates CCD File 
B [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.473α = 90
b = 79.473β = 90
c = 105.209γ = 120
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
CNSrefinement
HKL-2000data reduction
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-06-01
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Database references, Derived calculations