3TD8

Structural Analysis of Pneumocystis carinii Dihydrofolate Reductase Complex with NADPH and 2,4-diamino-5-methyl-6-[2'-(4-carboxy-1-pentynyl)-5'-methoxybenzyl]pyrido[2,3-d]pyrimidine


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.200 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Structural analysis of Pneumocystis cariniidihydrofolate reductase complexed with NADPH and 2,4-diamino-6-[2-(5-carboxypent-1-yn-1-yl)-5-methoxybenzyl]-5-methylpyrido[2,3-d]pyrimidine.

Cody, V.Pace, J.Stewart, E.

(2012) Acta Crystallogr Sect F Struct Biol Cryst Commun 68: 418-423

  • DOI: 10.1107/S1744309112008688
  • Primary Citation of Related Structures:  
    3TD8

  • PubMed Abstract: 
  • Structural data are reported for 2,4-diamino-6-[2-(5-carboxypent-1-yn-1-yl)-5-methoxybenzyl]-5-methylpyrido[2,3-d]pyrimidine (PY1014) complexed with Pneumocystis carinii dihydrofolate reductase (pcDHFR) refined to 1.8 Å resolution. These data reveal that the carboxylate of the ω-carboxyalkynyl side chain of PY1014, the most pcDHFR-selective analog in this series, forms ionic interactions with the conserved Arg75 in the substrate-binding pocket of pcDHFR ...

    Structural data are reported for 2,4-diamino-6-[2-(5-carboxypent-1-yn-1-yl)-5-methoxybenzyl]-5-methylpyrido[2,3-d]pyrimidine (PY1014) complexed with Pneumocystis carinii dihydrofolate reductase (pcDHFR) refined to 1.8 Å resolution. These data reveal that the carboxylate of the ω-carboxyalkynyl side chain of PY1014, the most pcDHFR-selective analog in this series, forms ionic interactions with the conserved Arg75 in the substrate-binding pocket of pcDHFR. The reversal of the 2',5'-substitution pattern of this analog compared with the highly selective diaminopyrimidine analog PY1011 (i.e. the 5'-pentynylcarboxy-5'-methoxy pattern of PY1014 versus the 3',4'-dimethoxy-5'-pentynylcarboxy pattern of PY1011) is necessary to achieve optimal interaction with Arg75 as observed in other structures. The larger diaminopyrido[2,3-d]pyrimidine ring of PY1014 places the 5'-methoxy group closer to Leu25 and Ser64 than does the diaminopyrimidine ring of PY1011. The 5'-methoxy O atom forms a hydrogen bond to the amide of Leu25 (O···N, 2.7 Å) and the 5'-methoxy methyl group makes a hydrophobic contact of 3.1 Å with C(β) of Ser64. Although the IC(50) values of PY1014 and PY1011 are similar, inhibition data show that the selectivity of PY1011 for pcDHFR is significantly greater. The greater selectivity for pcDHFR compared with mammalian DHFR of these inhibitors is also influenced by the enhanced hydrophobic interactions of the side-chain methylene atoms with Phe69 of pcDHFR compared with Asn64 of mammalian DHFR.


    Organizational Affiliation

    Structural Biology Department, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA. cody@hwi.buffalo.edu



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Dihydrofolate reductaseA206Pneumocystis cariniiMutation(s): 0 
EC: 1.5.1.3
Find proteins for P16184 (Pneumocystis carinii)
Explore P16184 
Go to UniProtKB:  P16184
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / 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
 Ligand Interaction
D2R
Query on D2R

Download Ideal Coordinates CCD File 
C [auth A]6-{2-[(2,4-diamino-5-methylpyrido[2,3-d]pyrimidin-6-yl)methyl]-4-methoxyphenyl}hex-5-ynoic acid
C22 H23 N5 O3
MAWHZPJVFGJFTF-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
D2RIC50:  1.2000000476837158   nM  BindingDB
D2RIC50:  1.2000000476837158   nM  Binding MOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.200 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.123α = 90
b = 42.63β = 95.2
c = 59.894γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
MOLREPphasing
REFMACrefinement
DENZOdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-04-11
    Type: Initial release
  • Version 1.1: 2012-05-02
    Changes: Database references