4DJK

Structure of glutamate-GABA antiporter GadC


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.097 Å
  • R-Value Free: 0.325 
  • R-Value Work: 0.282 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure and mechanism of a glutamate-GABA antiporter

Ma, D.Lu, P.L.Yan, C.Y.Fan, C.Yin, P.Wang, J.W.Shi, Y.G.

(2012) Nature 483: 632-636

  • DOI: 10.1038/nature10917
  • Primary Citation of Related Structures:  4DJI

  • PubMed Abstract: 
  • Food-borne hemorrhagic Escherichia coli, exemplified by the strains O157:H7 and O104:H4 (refs 1, 2), require elaborate acid-resistance systems (ARs) to survive the extremely acidic environment such as the stomach (pH ≈ 2). AR2 expels intracellular pr ...

    Food-borne hemorrhagic Escherichia coli, exemplified by the strains O157:H7 and O104:H4 (refs 1, 2), require elaborate acid-resistance systems (ARs) to survive the extremely acidic environment such as the stomach (pH ≈ 2). AR2 expels intracellular protons through the decarboxylation of L-glutamate (Glu) in the cytoplasm and exchange of the reaction product γ-aminobutyric acid (GABA) with extracellular Glu. The latter process is mediated by the Glu-GABA antiporter GadC, a representative member of the amino-acid-polyamine-organocation superfamily of membrane transporters. The functional mechanism of GadC remains largely unknown. Here we show, with the use of an in vitro proteoliposome-based assay, that GadC transports GABA/Glu only under acidic conditions, with no detectable activity at pH  values higher than 6.5. We determined the crystal structure of E. coli GadC at 3.1 Å resolution under basic conditions. GadC, comprising 12 transmembrane segments (TMs), exists in a closed state, with its carboxy-terminal domain serving as a plug to block an otherwise inward-open conformation. Structural and biochemical analyses reveal the essential transport residues, identify the transport path and suggest a conserved transport mechanism involving the rigid-body rotation of a helical bundle for GadC and other amino acid antiporters.


    Organizational Affiliation

    Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua University, Beijing 100084, China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Probable glutamate/gamma-aminobutyrate antiporter
A, B
511Escherichia coli (strain K12)Gene Names: gadC (acsA, xasA)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Amino Acid/Polyamine/Organocation (APC) Superfamily
Protein: 
GadC glutamate-GABA antiporter
Find proteins for P63235 (Escherichia coli (strain K12))
Go to UniProtKB:  P63235
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.097 Å
  • R-Value Free: 0.325 
  • R-Value Work: 0.282 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 71.962α = 90.00
b = 106.408β = 90.00
c = 185.982γ = 90.00
Software Package:
Software NamePurpose
CBASSdata collection
SHELXSphasing
HKL-2000data reduction
PHENIXrefinement
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-03-14
    Type: Initial release
  • Version 1.1: 2012-04-04
    Type: Database references