2R5C

Aedes Kynurenine Aminotransferase in Complex with Cysteine


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.96 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.220 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural insight into the mechanism of substrate specificity of aedes kynurenine aminotransferase.

Han, Q.Gao, Y.G.Robinson, H.Li, J.

(2008) Biochemistry 47: 1622-1630

  • DOI: 10.1021/bi701800j
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Aedes aegypti kynurenine aminotransferase (AeKAT) is a multifunctional aminotransferase. It catalyzes the transamination of a number of amino acids and uses many biologically relevant alpha-keto acids as amino group acceptors. AeKAT also is a cystein ...

    Aedes aegypti kynurenine aminotransferase (AeKAT) is a multifunctional aminotransferase. It catalyzes the transamination of a number of amino acids and uses many biologically relevant alpha-keto acids as amino group acceptors. AeKAT also is a cysteine S-conjugate beta-lyase. The most important function of AeKAT is the biosynthesis of kynurenic acid, a natural antagonist of NMDA and alpha7-nicotinic acetylcholine receptors. Here, we report the crystal structures of AeKAT in complex with its best amino acid substrates, glutamine and cysteine. Glutamine is found in both subunits of the biological dimer, and cysteine is found in one of the two subunits. Both substrates form external aldemines with pyridoxal 5-phosphate in the structures. This is the first instance in which one pyridoxal 5-phosphate enzyme has been crystallized with cysteine or glutamine forming external aldimine complexes, cysteinyl aldimine and glutaminyl aldimine. All the units with substrate are in the closed conformation form, and the unit without substrate is in the open form, which suggests that the binding of substrate induces the conformation change of AeKAT. By comparing the active site residues of the AeKAT-cysteine structure with those of the human KAT I-phenylalanine structure, we determined that Tyr286 in AeKAT is changed to Phe278 in human KAT I, which may explain why AeKAT transaminates hydrophilic amino acids more efficiently than human KAT I does.


    Organizational Affiliation

    Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Kynurenine aminotransferase
A
429Aedes aegyptiMutation(s): 0 
Gene Names: KAT
Find proteins for Q95VY4 (Aedes aegypti)
Go to UniProtKB:  Q95VY4
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Kynurenine aminotransferase
B
429Aedes aegyptiMutation(s): 0 
Gene Names: KAT
Find proteins for Q95VY4 (Aedes aegypti)
Go to UniProtKB:  Q95VY4
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
C6P
Query on C6P

Download SDF File 
Download CCD File 
B
N-({3-HYDROXY-2-METHYL-5-[(PHOSPHONOOXY)METHYL]PYRIDIN-4-YL}METHYL)-L-CYSTEINE
4-((1-CARBOXY-2-THIOL-ETHYLAMINO)-METHYL)-3-HYDROXY-2-METHYL-5-PHOSPHONOOXYMETHYL-PYRIDINIUM
C11 H17 N2 O7 P S
FPVGQJHHLSVHOT-VIFPVBQESA-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: 1.96 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.220 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 56.050α = 90.00
b = 95.678β = 90.00
c = 166.752γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-03-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance