Crystal Structure of Inhibitor Complex of Putative Pteridine Reductase 2 (PTR2) from Trypanosoma cruzi

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 

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Crystal structure of Trypanosoma cruzi pteridine reductase 2 in complex with a substrate and an inhibitor.

Schormann, N.Pal, B.Senkovich, O.Carson, M.Howard, A.Smith, C.Delucas, L.Chattopadhyay, D.

(2005) J Struct Biol 152: 64-75

  • DOI: https://doi.org/10.1016/j.jsb.2005.07.008
  • Primary Citation of Related Structures:  
    1MXF, 1MXH

  • PubMed Abstract: 

    Reduced pteridines are required for a number of important cellular functions. Trypanosomatid parasites, unlike their mammalian hosts, are pteridine auxotrophs and salvage the precursor pteridines from the host and reduce them to the respective biologically active tetrahydro forms using parasite-encoded enzymes. These enzymes may offer selective drug targets. In Leishmania, pteridine reductase 1 (PTR1), the primary enzyme for reducing pterins, is also responsible for resistance to antifolate drugs. Typically, PTR1 is more active with fully oxidized biopterin and folate than with their reduced counterparts. We have identified an enzyme, TcPTR2 of Trypanosoma cruzi, which though very similar to PTR1 in its primary sequence, can reduce only dihydrobiopterin and dihydrofolate and not oxidized pteridines. The structures of an inhibitor (methotrexate) and a substrate (dihydrofolate) complex of this enzyme demonstrate that the orientation of the substrate and the inhibitor in the active site of TcPTR2 are different from each other. However, the orientation of each ligand is similar to that of the corresponding ligand in Leishmania major PTR1 complexes.

  • Organizational Affiliation

    Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D
276Trypanosoma cruziMutation(s): 0 
Gene Names: ptr2
Find proteins for Q8I814 (Trypanosoma cruzi)
Explore Q8I814 
Go to UniProtKB:  Q8I814
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8I814
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B, C, D
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 
  • Space Group: P 31
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.79α = 90
b = 74.79β = 90
c = 180.99γ = 120
Software Package:
Software NamePurpose
HKL-2000data collection
X-GENdata reduction
HKL-2000data reduction
X-GENdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-10-14
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description