2COG

Crystal structure of oxidized human cytosolic branched-chain aminotransferase complexed with 4-methylvalerate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.233 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural determinants for branched-chain aminotransferase isozyme-specific inhibition by the anticonvulsant drug gabapentin

Goto, M.Miyahara, I.Hirotsu, K.Conway, M.Yennawar, N.Islam, M.M.Hutson, S.M.

(2005) J Biol Chem 280: 37246-37256

  • DOI: 10.1074/jbc.M506486200
  • Primary Citation of Related Structures:  
    2A1H, 2COJ, 2COI, 2COG

  • PubMed Abstract: 
  • This study presents the first three-dimensional structures of human cytosolic branched-chain aminotransferase (hBCATc) isozyme complexed with the neuroactive drug gabapentin, the hBCATc Michaelis complex with the substrate analog, 4-methylvalerate, a ...

    This study presents the first three-dimensional structures of human cytosolic branched-chain aminotransferase (hBCATc) isozyme complexed with the neuroactive drug gabapentin, the hBCATc Michaelis complex with the substrate analog, 4-methylvalerate, and the mitochondrial isozyme (hBCATm) complexed with gabapentin. The branched-chain aminotransferases (BCAT) reversibly catalyze transamination of the essential branched-chain amino acids (leucine, isoleucine, valine) to alpha-ketoglutarate to form the respective branched-chain alpha-keto acids and glutamate. The cytosolic isozyme is the predominant BCAT found in the nervous system, and only hBCATc is inhibited by gabapentin. Pre-steady state kinetics show that 1.3 mm gabapentin can completely inhibit the binding of leucine to reduced hBCATc, whereas 65.4 mm gabapentin is required to inhibit leucine binding to hBCATm. Structural analysis shows that the bulky gabapentin is enclosed in the active-site cavity by the shift of a flexible loop that enlarges the active-site cavity. The specificity of gabapentin for the cytosolic isozyme is ascribed at least in part to the location of the interdomain loop and the relative orientation between the small and large domain which is different from these relationships in the mitochondrial isozyme. Both isozymes contain a CXXC center and form a disulfide bond under oxidizing conditions. The structure of reduced hBCATc was obtained by soaking the oxidized hBCATc crystals with dithiothreitol. The close similarity in active-site structures between cytosolic enzyme complexes in the oxidized and reduced states is consistent with the small effect of oxidation on pre-steady state kinetics of the hBCATc first half-reaction. However, these kinetic data do not explain the inactivation of hBCATm by oxidation of the CXXC center. The structural data suggest that there is a larger effect of oxidation on the interdomain loop and residues surrounding the CXXC center in hBCATm than in hBCATc.


    Organizational Affiliation

    Department of Chemistry, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
branched chain aminotransferase 1, cytosolicAB386Homo sapiensMutation(s): 1 
Gene Names: BCAT1BCT1ECA39
EC: 2.6.1.42
Find proteins for P54687 (Homo sapiens)
Explore P54687 
Go to UniProtKB:  P54687
NIH Common Fund Data Resources
PHAROS  P54687
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PLP
Query on PLP

Download CCD File 
A, B
PYRIDOXAL-5'-PHOSPHATE
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
 Ligand Interaction
4MV
Query on 4MV

Download CCD File 
A, B
4-METHYL VALERIC ACID
C6 H12 O2
FGKJLKRYENPLQH-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

Download CCD File 
B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.233 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.82α = 90
b = 106.9β = 90
c = 110.11γ = 90
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2005-05-17 
  • Released Date: 2005-08-30 
  • Deposition Author(s): Goto, M.

Revision History 

  • Version 1.0: 2005-08-30
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance