2Q7W

Structural Studies Reveals the Inactivation of E. coli L-aspartate aminotransferase (S)-4,5-amino-dihydro-2-thiophenecarboxylic acid (SADTA) via two mechanisms at pH 6.0


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.188 
  • R-Value Work: 0.154 
  • R-Value Observed: 0.156 

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


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:  
    2Q7W, 2QA3, 2QB2, 2QB3, 2QBT

  • 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 models with high resolution (1 ...

    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:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Aspartate aminotransferaseA396Escherichia coliMutation(s): 1 
Gene Names: aspC
EC: 2.6.1.1
UniProt
Find proteins for P00509 (Escherichia coli (strain K12))
Explore P00509 
Go to UniProtKB:  P00509
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00509
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PSZ
Query on PSZ

Download Ideal Coordinates CCD File 
C [auth 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

Download Ideal Coordinates CCD File 
D [auth A]4'-DEOXY-4'-AMINOPYRIDOXAL-5'-PHOSPHATE
C8 H13 N2 O5 P
ZMJGSOSNSPKHNH-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download Ideal Coordinates CCD File 
B [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A],
N [auth A],
O [auth A]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-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: 1.40 Å
  • R-Value Free: 0.188 
  • R-Value Work: 0.154 
  • R-Value Observed: 0.156 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 153.623α = 90
b = 85.135β = 90
c = 78.849γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-09-04
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Version format compliance