2OKK

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

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.200 

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, 2OKK

  • 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, 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 ...

    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
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Glutamate decarboxylase 2A497Homo sapiensMutation(s): 0 
Gene Names: GAD2, GAD65
EC: 4.1.1.15
UniProt & NIH Common Fund Data Resources
Find proteins for Q05329 (Homo sapiens)
Explore Q05329 
Go to UniProtKB:  Q05329
PHAROS:  Q05329
GTEx:  ENSG00000136750 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ05329
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ABU
Query on ABU
Download Ideal Coordinates CCD File 
B [auth A],
C [auth A]		GAMMA-AMINO-BUTANOIC ACID
C4 H9 N O2
BTCSSZJGUNDROE-UHFFFAOYSA-N		 Ligand Interaction
GOL
Query on GOL
Download Ideal Coordinates CCD File 
D [auth A]GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-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: 2.30 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.200 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78.251α = 90
b = 99.057β = 90
c = 120.009γ = 90
Software Package:
Software NamePurpose
SCALAdata scaling
ADSCdata collection
HKL-2000data reduction
CCP4data scaling
PHASERphasing
REFMACrefinement

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

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