6ND2

Staphylococcus aureus Dihydrofolate Reductase complexed with NADPH and 6-ETHYL-5-[(3R)-3-[2-METHOXY-5-(PYRIDIN-4-YL)PHENYL]BUT-1-YN-1-YL]PYRIMIDINE-2,4-DIAMINE (UCP1063)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.24 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.190 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Structure-Guided In Vitro to In Vivo Pharmacokinetic Optimization of Propargyl-Linked Antifolates.

Lombardo, M.N.G-Dayanandan, N.Keshipeddy, S.Zhou, W.Si, D.Reeve, S.M.Alverson, J.Barney, P.Walker, L.Hoody, J.Priestley, N.D.Obach, R.S.Wright, D.L.

(2019) Drug Metab Dispos 47: 995-1003

  • DOI: https://doi.org/10.1124/dmd.119.086504
  • Primary Citation of Related Structures:  
    6ND2

  • PubMed Abstract: 

    Pharmacokinetic/pharmacodynamic properties are strongly correlated with the in vivo efficacy of antibiotics. Propargyl-linked antifolates, a novel class of antibiotics, demonstrate potent antibacterial activity against both Gram-positive and Gram-negative pathogenic bacteria, including multidrug-resistant Staphylococcus aureus Here, we report our efforts to optimize the pharmacokinetic profile of this class to best match the established pharmacodynamic properties. High-resolution crystal structures were used in combination with in vitro pharmacokinetic models to design compounds that not only are metabolically stable in vivo but also retain potent antibacterial activity. The initial lead compound was prone to both N -oxidation and demethylation, which resulted in an abbreviated in vivo half-life (∼20 minutes) in mice. Stability of leads toward mouse liver microsomes was primarily used to guide medicinal chemistry efforts so robust efficacy could be demonstrated in a mouse disease model. Structure-based drug design guided mitigation of N -oxide formation through substitutions of sterically demanding groups adjacent to the pyridyl nitrogen. Additionally, deuterium and fluorine substitutions were evaluated for their effect on the rate of oxidative demethylation. The resulting compound was characterized and demonstrated to have a low projected clearance in humans with limited potential for drug-drug interactions as predicted by cytochrome P450 inhibition as well as an in vivo exposure profile that optimizes the potential for bactericidal activity, highlighting how structural data, merged with substitutions to introduce metabolic stability, are a powerful approach to drug design.


  • Organizational Affiliation

    Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (M.N.L., N.G.-D., S.K., W.Z., D.S., S.M.R., D.L.W.); Pfizer Worldwide Research & Development, Pharmacokinetics, Dynamics, and Metabolism, Groton, Connecticut (R.S.O.); and Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana (J.A., P.B., L.W., J.H., N.D.P.).


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Dihydrofolate reductaseA [auth X]157Staphylococcus aureusMutation(s): 0 
Gene Names: folA
EC: 1.5.1.3
UniProt
Find proteins for P0A017 (Staphylococcus aureus)
Explore P0A017 
Go to UniProtKB:  P0A017
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A017
Sequence Annotations
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
G8J BindingDB:  6ND2 Ki: 4.5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.24 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.190 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78.878α = 90
b = 78.878β = 90
c = 107.908γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI104841
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI111957

Revision History  (Full details and data files)

  • Version 1.0: 2019-09-25
    Type: Initial release
  • Version 1.1: 2019-12-18
    Changes: Author supporting evidence
  • Version 1.2: 2023-10-11
    Changes: Data collection, Database references, Refinement description