2QA3

Structural Studies Reveal the Inactivation of E. coli L-aspartate aminotransferase by (S)-4,5-amino-dihydro-2-thiophenecarboxylic acid (SADTA) via two mechanisms (at pH6.5)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.154 

wwPDB Validation 3D Report Full Report


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Literature

Inactivation of Escherichia coli L-aspartate aminotransferase by (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid reveals "a tale of two mechanisms".

Liu, D.Pozharski, E.Lepore, B.W.Fu, M.Silverman, R.B.Petsko, G.A.Ringe, D.

(2007) Biochemistry 46: 10517-10527

  • DOI: 10.1021/bi700663n
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • As a mechanism-based inactivator of PLP-enzymes, (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid (SADTA) was cocrystallized with Escherichia coli aspartate aminotransferase (l-AspAT) at a series of pH values ranging from 6 to 8. Five structural mo ...

    As a mechanism-based inactivator of PLP-enzymes, (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid (SADTA) was cocrystallized with Escherichia coli aspartate aminotransferase (l-AspAT) at a series of pH values ranging from 6 to 8. Five structural models with high resolution (1.4-1.85 A) were obtained for l-AspAT-SADTA complexes at pH 6.0, 6.5, 7.0, 7.5, and 8.0. Electron densities of the models showed that two different adducts had formed in the active sites. One adduct was formed from SADTA covalently linked to pyridoxal 5'-phosphate (PLP) while the other adduct was formed with the inhibitor covalently linked to Lysine246,1 the active site lysine. Moreover, there is a strong indication based on the electron densities that the occurrence of the two adducts is pH dependent. We conclude that SADTA inactivates l-AspAT via two different mechanisms based on the binding direction of the inactivator. Additionally, the structural models also show pH dependence of the protein structure itself, which provided detailed mechanistic implications for l-AspAT.


    Organizational Affiliation

    Department of Biochemistry and Chemistry and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts 02454-9110, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Aspartate aminotransferase
A
396Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: aspC
EC: 2.6.1.1
Find proteins for P00509 (Escherichia coli (strain K12))
Go to UniProtKB:  P00509
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

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

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Download CCD File 
A
4-[({3-HYDROXY-2-METHYL-5-[(PHOSPHONOOXY)METHYL]PYRIDIN-4-YL}METHYL)AMINO]THIOPHENE-2-CARBOXYLIC ACID
C13 H15 N2 O7 P S
SUKBSASAEROGCJ-UHFFFAOYSA-N
 Ligand Interaction
PMP
Query on PMP

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Download CCD File 
A
4'-DEOXY-4'-AMINOPYRIDOXAL-5'-PHOSPHATE
PYRIDOXAMINE-5'-PHOSPHATE
C8 H13 N2 O5 P
ZMJGSOSNSPKHNH-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
KST
Query on KST
A
L-PEPTIDE LINKINGC11 H16 N2 O4 SLYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.154 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 153.897α = 90.00
b = 84.900β = 90.00
c = 78.877γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
PHASERphasing
HKL-2000data reduction
HKL-2000data scaling
REFMACrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-12-04
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Derived calculations, Version format compliance