2QHX

Structure of Pteridine Reductase from Leishmania major complexed with a ligand

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.183 

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This is version 1.2 of the entry. See complete history. 


Literature

Discovery of potent pteridine reductase inhibitors to guide antiparasite drug development.

Cavazzuti, A., Paglietti, G., Hunter, W.N., Gamarro, F., Piras, S., Loriga, M., Allecca, S., Corona, P., McLuskey, K., Tulloch, L., Gibellini, F., Ferrari, S., Costi, M.P.

(2008) Proc Natl Acad Sci U S A 105: 1448-1453

  • DOI: 10.1073/pnas.0704384105
  • Primary Citation of Related Structures:  
    2QHX, 3H4V

  • PubMed Abstract: 

    • Pteridine reductase (PTR1) is essential for salvage of pterins by parasitic trypanosomatids and is a target for the development of improved therapies. To identify inhibitors of Leishmania major and Trypanosoma cruzi PTR1, we combined a rapid-screening strategy using a folate-based library with structure-based design ...

    Pteridine reductase (PTR1) is essential for salvage of pterins by parasitic trypanosomatids and is a target for the development of improved therapies. To identify inhibitors of Leishmania major and Trypanosoma cruzi PTR1, we combined a rapid-screening strategy using a folate-based library with structure-based design. Assays were carried out against folate-dependent enzymes including PTR1, dihydrofolate reductase (DHFR), and thymidylate synthase. Affinity profiling determined selectivity and specificity of a series of quinoxaline and 2,4-diaminopteridine derivatives, and nine compounds showed greater activity against parasite enzymes compared with human enzymes. Compound 6a displayed a K(i) of 100 nM toward LmPTR1, and the crystal structure of the LmPTR1:NADPH:6a ternary complex revealed a substrate-like binding mode distinct from that previously observed for similar compounds. A second round of design, synthesis, and assay produced a compound (6b) with a significantly improved K(i) (37 nM) against LmPTR1, and the structure of this complex was also determined. Biological evaluation of selected inhibitors was performed against the extracellular forms of T. cruzi and L. major, both wild-type and overexpressing PTR1 lines, as a model for PTR1-driven antifolate drug resistance and the intracellular form of T. cruzi. An additive profile was observed when PTR1 inhibitors were used in combination with known DHFR inhibitors, and a reduction in toxicity of treatment was observed with respect to administration of a DHFR inhibitor alone. The successful combination of antifolates targeting two enzymes indicates high potential for such an approach in the development of previously undescribed antiparasitic drugs.

    Organizational Affiliation: 

    Dipartimento di Scienze Farmaceutiche, Università di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Pteridine reductase 1A, B, C, D328Leishmania majorMutation(s): 1 
Gene Names: PTR1, HMTXR, L1063.01, LmjF23.0270, LmjF_23_0270
EC: 1.5.1.33
UniProt
Find proteins for Q01782 (Leishmania major)
Explore Q01782 
Go to UniProtKB:  Q01782
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ01782
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAP
Query on NAP
Download Ideal Coordinates CCD File 
F [auth A],
I [auth B],
K [auth C],
M [auth D]		NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE
C21 H28 N7 O17 P3
XJLXINKUBYWONI-NNYOXOHSSA-N		 Ligand Interaction
FE1
Query on FE1
Download Ideal Coordinates CCD File 
G [auth A],
J [auth B],
L [auth C],
N [auth D]		METHYL 1-(4-{[(2,4-DIAMINOPTERIDIN-6-YL)METHYL](METHYL)AMINO}BENZOYL)PIPERIDINE-4-CARBOXYLATE
C22 H26 N8 O3
UKCFUFHREWUXJJ-UHFFFAOYSA-N		 Ligand Interaction
IOD
Query on IOD
Download Ideal Coordinates CCD File 
E [auth A],
H [auth B]		IODIDE ION
I
XMBWDFGMSWQBCA-UHFFFAOYSA-M		 Ligand Interaction
Binding Affinity Annotations 
IDSourceBinding Affinity
FE1 BindingDB:  2QHX Ki: 37 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.183 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 95.499α = 90
b = 104.231β = 90
c = 136.865γ = 90
Software Package:
Software NamePurpose
MOLREPphasing
REFMACrefinement
CrystalCleardata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-12-25
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references, Derived calculations