4N0D

Crystal structure of the K345L variant of the Gi alpha1 subunit bound to GTPgammaS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.187 
  • R-Value Work: 0.157 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

A Transient Interaction between the Phosphate Binding Loop and Switch I Contributes to the Allosteric Network between Receptor and Nucleotide in G alpha i1.

Thaker, T.M.Sarwar, M.Preininger, A.M.Hamm, H.E.Iverson, T.M.

(2014) J.Biol.Chem. 289: 11331-11341

  • DOI: 10.1074/jbc.M113.539064
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Receptor-mediated activation of the Gα subunit of heterotrimeric G proteins requires allosteric communication between the receptor binding site and the guanine nucleotide binding site, which are separated by >30 Å. Structural changes in the allosteri ...

    Receptor-mediated activation of the Gα subunit of heterotrimeric G proteins requires allosteric communication between the receptor binding site and the guanine nucleotide binding site, which are separated by >30 Å. Structural changes in the allosteric network connecting these sites are predicted to be transient in the wild-type Gα subunit, making studies of these connections challenging. In the current work, site-directed mutants that alter the energy barriers between the activation states are used as tools to better understand the transient features of allosteric signaling in the Gα subunit. The observed differences in relative receptor affinity for intact Gαi1 subunits versus C-terminal Gαi1 peptides harboring the K345L mutation are consistent with this mutation modulating the allosteric network in the protein subunit. Measurement of nucleotide exchange rates, affinity for metarhodopsin II, and thermostability suggest that the K345L Gαi1 variant has reduced stability in both the GDP-bound and nucleotide-free states as compared with wild type but similar stability in the GTPγS-bound state. High resolution x-ray crystal structures reveal conformational changes accompanying the destabilization of the GDP-bound state. Of these, the conformation for Switch I was stabilized by an ionic interaction with the phosphate binding loop. Further site-directed mutagenesis suggests that this interaction between Switch I and the phosphate binding loop is important for receptor-mediated nucleotide exchange in the wild-type Gαi1 subunit.


    Organizational Affiliation

    From the Department of Biochemistry and.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Guanine nucleotide-binding protein G(i) subunit alpha-1
A
356Rattus norvegicusMutation(s): 1 
Gene Names: Gnai1 (Gnai-1)
Find proteins for P10824 (Rattus norvegicus)
Go to UniProtKB:  P10824
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO3
Query on SO3

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Download CCD File 
A
SULFITE ION
O3 S
LSNNMFCWUKXFEE-UHFFFAOYSA-L
 Ligand Interaction
MG
Query on MG

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Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
GSP
Query on GSP

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Download CCD File 
A
5'-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE
C10 H16 N5 O13 P3 S
XOFLBQFBSOEHOG-UUOKFMHZSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.187 
  • R-Value Work: 0.157 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 79.635α = 90.00
b = 79.635β = 90.00
c = 104.825γ = 120.00
Software Package:
Software NamePurpose
PHASERphasing
SCALEPACKdata scaling
PHENIXrefinement
HKL-2000data reduction
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-03-12
    Type: Initial release
  • Version 1.1: 2014-04-02
    Type: Database references
  • Version 1.2: 2014-05-07
    Type: Database references
  • Version 1.3: 2014-11-12
    Type: Structure summary