4QHV

Crystal structure of human dihydrofolate reductase as complex with pyridopyrimidine 22 (N~6~-METHYL-N~6~-[4-(PROPAN-2-YL)PHENYL]PYRIDO[2,3-D]PYRIMIDINE-2,4,6-TRIAMINE)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.61 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Structure-activity correlations for three pyrido[2,3-d]pyrimidine antifolates binding to human and Pneumocystis carinii dihydrofolate reductase.

Cody, V.Pace, J.Namjoshi, O.A.Gangjee, A.

(2015) Acta Crystallogr Sect F Struct Biol Cryst Commun 71: 799-803

  • DOI: https://doi.org/10.1107/S2053230X15008468
  • Primary Citation of Related Structures:  
    4QHV, 4QJC, 4QJZ

  • PubMed Abstract: 

    To further define the interactions that enhance the selectivity of binding and to directly compare the binding of the most potent analogue {N(6)-methyl-N(6)-(3,4,5-trifluorophenyl)pyrido[2,3-d]pyrimidine-2,4,6-triamine; compound 26} in the series of bicyclic pyrido[2,3-d]pyrimidine analogues of piritrexim (PTX) with native human (h), Pneumocystis carinii (pc) and Pneumocystis jirovecii (pj) dihydrofolate reductase (DHFR) enzymes, the crystal structures of hDHFR complexed with N(6)-methyl-N(6)-(4-isopropylphenyl)pyrido[2,3-d]pyrimidine-2,4,6-triamine (compound 22), of hDHFR complexed with compound 26 and of pcDHFR complexed with N(6)-methyl-N(6)-1-naphthylpyrido[2,3-d]pyrimidine-2,4,6-triamine (compound 24) are reported as ternary complexes with NADPH. This series of bicyclic pyrido[2,3-d]pyrimidines were designed in which there was a transposition of the 5-methyl group of PTX to the N9 position of the pyrido[2,3-d]pyrimidine. It was hypothesized that the N9-methyl group would preferentially interact with Ile123 of pcDHFR (and Ile123 of pjDHFR), but not with the shorter Val115 in hDHFR. Structure-activity data for this series of antifolates revealed that a trifluoro derivative (26) was the most selective against pjDHFR compared with mammalian DHFR (h/pj = 35.7). Structural data for the hDHFR-26 complex revealed that 26 binds in a different conformation from that observed in the pcDHFR-26 complex. In the hDHFR-26 complex the trifluorophenyl ring of 26 occupies a position near the cofactor-binding site, with close intermolecular contacts with Asp21, Ser59 and Ile60, whereas this ring in the pcDHFR-26 complex is positioned away from the cofactor site and near Ile65, with weaker contacts with Ile65, Phe69 and Ile123. Comparison of the intermolecular contacts between the N9-methyl group with Val115/Ile123 validates the hypothesis that the N9-methyl substituent preferentially interacts with Ile123 compared with Val115 of hDHFR, as the weaker contact with Val115 in the hDHFR structure is consistent with its weaker binding affinity compared with pcDHFR. The results for the structures of hDHFR-22 and pcDHFR-24 show that their inhibitor-binding orientation is similar to that observed in pcDHFR-26 and the pcDHFR variant (F69N) reported previously. The naphthyl moiety of 24 makes several intermolecular contacts with the active-site residues in pcDHFR that help to stabilize the binding, resulting in a more potent inhibitor.


  • Organizational Affiliation

    Structural Biology Department, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Dihydrofolate reductase186Homo sapiensMutation(s): 0 
Gene Names: DHFR
EC: 1.5.1.3
UniProt & NIH Common Fund Data Resources
Find proteins for P00374 (Homo sapiens)
Explore P00374 
Go to UniProtKB:  P00374
PHAROS:  P00374
GTEx:  ENSG00000228716 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00374
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NDP
Query on NDP

Download Ideal Coordinates CCD File 
B [auth A]NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE
C21 H30 N7 O17 P3
ACFIXJIJDZMPPO-NNYOXOHSSA-N
IXF
Query on IXF

Download Ideal Coordinates CCD File 
C [auth A]N~6~-methyl-N~6~-[4-(propan-2-yl)phenyl]pyrido[2,3-d]pyrimidine-2,4,6-triamine
C17 H20 N6
CRSDIJKYSOUKQH-UHFFFAOYSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
G [auth A]
H [auth A]
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
Binding Affinity Annotations 
IDSourceBinding Affinity
IXF BindingDB:  4QHV Ki: 11 (nM) from 1 assay(s)
IC50: 52 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.61 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.393α = 90
b = 84.393β = 90
c = 78.333γ = 120
Software Package:
Software NamePurpose
XDSdata scaling
MOLREPphasing
REFMACrefinement
XDSdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

Deposition Data

  • Released Date: 2015-06-10 
  • Deposition Author(s): Cody, V.

Revision History  (Full details and data files)

  • Version 1.0: 2015-06-10
    Type: Initial release
  • Version 1.1: 2015-07-01
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Refinement description
  • Version 1.3: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description