6HOW

Trypanosoma brucei PTR1 in complex with the triazine inhibitor 2a (F219).


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.172 

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Literature

Structural Insights into the Development of Cycloguanil Derivatives asTrypanosoma bruceiPteridine-Reductase-1 Inhibitors.

Landi, G.Linciano, P.Borsari, C.Bertolacini, C.P.Moraes, C.B.Cordeiro-da-Silva, A.Gul, S.Witt, G.Kuzikov, M.Costi, M.P.Pozzi, C.Mangani, S.

(2019) ACS Infect Dis 5: 1105-1114

  • DOI: 10.1021/acsinfecdis.8b00358
  • Primary Citation of Related Structures:  
    6HNR, 6HNC, 6HOW

  • PubMed Abstract: 
  • Cycloguanil is a known dihydrofolate-reductase (DHFR) inhibitor, but there is no evidence of its activity on pteridine reductase (PTR), the main metabolic bypass to DHFR inhibition in trypanosomatid parasites. Here, we provide experimental evidence of cycloguanil as an inhibitor of Trypanosoma brucei PTR1 ( Tb PTR1) ...

    Cycloguanil is a known dihydrofolate-reductase (DHFR) inhibitor, but there is no evidence of its activity on pteridine reductase (PTR), the main metabolic bypass to DHFR inhibition in trypanosomatid parasites. Here, we provide experimental evidence of cycloguanil as an inhibitor of Trypanosoma brucei PTR1 ( Tb PTR1). A small library of cycloguanil derivatives was developed, resulting in 1 and 2a having IC 50 values of 692 and 186 nM, respectively, toward Tb PTR1. Structural analysis revealed that the increased potency of 1 and 2a is due to the combined contributions of hydrophobic interactions, H-bonds, and halogen bonds. Moreover, in vitro cell-growth-inhibition tests indicated that 2a is also effective on T. brucei . The simultaneous inhibition of DHFR and PTR1 activity in T. brucei is a promising new strategy for the treatment of human African trypanosomiasis. For this purpose, 1,6-dihydrotriazines represent new molecular tools to develop potent dual PTR and DHFR inhibitors.


    Organizational Affiliation

    Department of Biotechnology, Chemistry and Pharmacy-Department of Excellence 2018-2020 , University of Siena , via Aldo Moro 2 , 53100 Siena , Italy.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Pteridine reductaseA, B, C288Trypanosoma brucei bruceiMutation(s): 0 
Gene Names: PTR1
UniProt
Find proteins for O76290 (Trypanosoma brucei brucei)
Explore O76290 
Go to UniProtKB:  O76290
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Pteridine reductaseD288Trypanosoma brucei bruceiMutation(s): 0 
Gene Names: PTR1
UniProt
Find proteins for O76290 (Trypanosoma brucei brucei)
Explore O76290 
Go to UniProtKB:  O76290
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAP (Subject of Investigation/LOI)
Query on NAP

Download Ideal Coordinates CCD File 
E [auth A], G [auth B], I [auth C], J [auth D]NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE
C21 H28 N7 O17 P3
XJLXINKUBYWONI-NNYOXOHSSA-N
 Ligand Interaction
GJQ (Subject of Investigation/LOI)
Query on GJQ

Download Ideal Coordinates CCD File 
F [auth A], H [auth B], K [auth D](2~{R})-1-(3,4-dichlorophenyl)-2-(4-nitrophenyl)-2~{H}-1,3,5-triazine-4,6-diamine
C15 H12 Cl2 N6 O2
GMVZOQXAUORTLW-CYBMUJFWSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CSX
Query on CSX
DL-PEPTIDE LINKINGC3 H7 N O3 SCYS
Binding Affinity Annotations 
IDSourceBinding Affinity
GJQ Binding MOAD:  6HOW IC50: 186 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.172 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.674α = 90
b = 91.042β = 115.59
c = 83.001γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
SCALAdata scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
European Commission603240

Revision History  (Full details and data files)

  • Version 1.0: 2019-05-08
    Type: Initial release
  • Version 1.1: 2019-07-24
    Changes: Data collection, Database references