Investigation of Aminopyridiopyrazinones as PDE5 Inhibitors: Evaluation of Modifications to the Central Ring System.

Experimental Data Snapshot

  • Resolution: 1.79 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 

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This is version 1.6 of the entry. See complete history


Investigation of aminopyridiopyrazinones as PDE5 inhibitors: Evaluation of modifications to the central ring system.

Hughes, R.O.Walker, J.K.Cubbage, J.W.Fobian, Y.M.Rogier, D.J.Heasley, S.E.Blevis-Bal, R.M.Benson, A.G.Owen, D.R.Jacobsen, E.J.Freskos, J.N.Molyneaux, J.M.Brown, D.L.Stallings, W.C.Acker, B.A.Maddux, T.M.Tollefson, M.B.Williams, J.M.Moon, J.B.Mischke, B.V.Rumsey, J.M.Zheng, Y.Macinnes, A.Bond, B.R.Yu, Y.

(2009) Bioorg Med Chem Lett 19: 4092-4096

  • DOI: https://doi.org/10.1016/j.bmcl.2009.06.004
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Efforts to improve the potency and physical properties of the aminopyridiopyrazinone class of PDE5 inhibitors through modification of the core ring system are described. Five new ring systems are evaluated and features that impart improved potency and improved solubility are delineated.

  • Organizational Affiliation

    Pfizer Global Research and Development, Chesterfield Parkway West, St. Louis, MO 63017, USA. robert.o.hughes@pfizer.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
cGMP-specific 3',5'-cyclic phosphodiesterase,cAMP-specific 3',5'-cyclic phosphodiesterase 4A324Homo sapiensMutation(s): 0 
EC: (PDB Primary Data), (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for O76074 (Homo sapiens)
Explore O76074 
Go to UniProtKB:  O76074
PHAROS:  O76074
GTEx:  ENSG00000138735 
Find proteins for P27815 (Homo sapiens)
Explore P27815 
Go to UniProtKB:  P27815
PHAROS:  P27815
GTEx:  ENSG00000065989 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsP27815O76074
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
PD4 Binding MOAD:  3HC8 IC50: 2.9 (nM) from 1 assay(s)
BindingDB:  3HC8 IC50: min: 2.4, max: 2.9 (nM) from 2 assay(s)
PDBBind:  3HC8 IC50: 2.9 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.79 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.691α = 90
b = 77.085β = 101.93
c = 77.514γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-07
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-06-21
    Changes: Advisory, Database references, Source and taxonomy, Structure summary
  • Version 1.3: 2017-11-01
    Changes: Refinement description
  • Version 1.4: 2018-01-24
    Changes: Structure summary
  • Version 1.5: 2023-07-26
    Changes: Database references, Derived calculations
  • Version 1.6: 2024-05-22
    Changes: Data collection