2GKE

Crystal structure of diaminopimelate epimerase in complex with an irreversible inhibitor LL-AziDAP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.35 Å
  • R-Value Free: 0.168 
  • R-Value Work: 0.138 
  • R-Value Observed: 0.139 

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This is version 1.2 of the entry. See complete history


Literature

Structural insights into stereochemical inversion by diaminopimelate epimerase: An antibacterial drug target.

Pillai, B.Cherney, M.M.Diaper, C.M.Sutherland, A.Blanchard, J.S.Vederas, J.C.James, M.N.

(2006) Proc Natl Acad Sci U S A 103: 8668-8673

  • DOI: https://doi.org/10.1073/pnas.0602537103
  • Primary Citation of Related Structures:  
    2GKE, 2GKJ

  • PubMed Abstract: 

    D-amino acids are much less common than their L-isomers but are widely distributed in most organisms. Many D-amino acids, including those necessary for bacterial cell wall formation, are synthesized from the corresponding L-isomers by alpha-amino acid racemases. The important class of pyridoxal phosphate-independent racemases function by an unusual mechanism whose details have been poorly understood. It has been proposed that the stereoinversion involves two active-site cysteine residues acting in concert as a base (thiolate) and an acid (thiol). Although crystallographic structures of several such enzymes are available, with the exception of the recent structures of glutamate racemase from Bacillus subtilis and of proline racemase from Trypanosoma cruzi, the structures either are of inactive forms (e.g., disulfide) or do not allow unambiguous modeling of the substrates in the active sites. Here, we present the crystal structures of diaminopimelate (DAP) epimerase from Haemophilus influenzae with two different isomers of the irreversible inhibitor and substrate mimic aziridino-DAP at 1.35- and 1.70-A resolution. These structures permit a detailed description of this pyridoxal 5'-phosphate-independent amino acid racemase active site and delineate the electrostatic interactions that control the exquisite substrate selectivity of DAP epimerase. Moreover, the active site shows how deprotonation of the substrates' nonacidic hydrogen at the alpha-carbon (pKa approximately 29) by a seemingly weakly basic cysteine residue (pKa approximately 8-10) is facilitated by interactions with two buried alpha-helices. Bacterial racemases, including glutamate racemase and DAP epimerase, are potential targets for the development of new agents effective against organisms resistant to conventional antibiotics.


  • Organizational Affiliation

    Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, AB, Canada T6G 2H7.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Diaminopimelate epimerase274Haemophilus influenzaeMutation(s): 0 
Gene Names: dapF
EC: 5.1.1.7
UniProt
Find proteins for P44859 (Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd))
Explore P44859 
Go to UniProtKB:  P44859
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP44859
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.35 Å
  • R-Value Free: 0.168 
  • R-Value Work: 0.138 
  • R-Value Observed: 0.139 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 96.394α = 90
b = 104.02β = 90
c = 59.936γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
Blu-Icedata collection
SCALEPACKdata scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-05-16
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance