2OKK

The X-ray crystal structure of the 65kDa isoform of Glutamic Acid Decarboxylase (GAD65)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.196 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

GABA production by glutamic acid decarboxylase is regulated by a dynamic catalytic loop.

Fenalti, G.Law, R.H.Buckle, A.M.Langendorf, C.Tuck, K.Rosado, C.J.Faux, N.G.Mahmood, K.Hampe, C.S.Banga, J.P.Wilce, M.Schmidberger, J.Rossjohn, J.El-Kabbani, O.Pike, R.N.Smith, A.I.Mackay, I.R.Rowley, M.J.Whisstock, J.C.

(2007) Nat.Struct.Mol.Biol. 14: 280-286

  • DOI: 10.1038/nsmb1228
  • Primary Citation of Related Structures:  2OKJ

  • PubMed Abstract: 
  • Gamma-aminobutyric acid (GABA) is synthesized by two isoforms of the pyridoxal 5'-phosphate-dependent enzyme glutamic acid decarboxylase (GAD65 and GAD67). GAD67 is constitutively active and is responsible for basal GABA production. In contrast, GAD6 ...

    Gamma-aminobutyric acid (GABA) is synthesized by two isoforms of the pyridoxal 5'-phosphate-dependent enzyme glutamic acid decarboxylase (GAD65 and GAD67). GAD67 is constitutively active and is responsible for basal GABA production. In contrast, GAD65, an autoantigen in type I diabetes, is transiently activated in response to the demand for extra GABA in neurotransmission, and cycles between an active holo form and an inactive apo form. We have determined the crystal structures of N-terminal truncations of both GAD isoforms. The structure of GAD67 shows a tethered loop covering the active site, providing a catalytic environment that sustains GABA production. In contrast, the same catalytic loop is inherently mobile in GAD65. Kinetic studies suggest that mobility in the catalytic loop promotes a side reaction that results in cofactor release and GAD65 autoinactivation. These data reveal the molecular basis for regulation of GABA homeostasis.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Monash University, Clayton, Melbourne, VIC 3800, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Glutamate decarboxylase 2
A
497Homo sapiensGene Names: GAD2 (GAD65)
EC: 4.1.1.15
Find proteins for Q05329 (Homo sapiens)
Go to Gene View: GAD2
Go to UniProtKB:  Q05329
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
ABU
Query on ABU

Download SDF File 
Download CCD File 
A
GAMMA-AMINO-BUTANOIC ACID
GAMMA(AMINO)-BUTYRIC ACID
C4 H9 N O2
BTCSSZJGUNDROE-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
LLP
Query on LLP
A
L-PEPTIDE LINKINGC14 H22 N3 O7 PLYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.196 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 78.251α = 90.00
b = 99.057β = 90.00
c = 120.009γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
CCP4data scaling
SCALAdata scaling
ADSCdata collection
HKL-2000data reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-03-27
    Type: Initial release
  • Version 1.1: 2007-10-16
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance