1EQG

THE 2.6 ANGSTROM MODEL OF OVINE COX-1 COMPLEXED WITH IBUPROFEN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.223 

wwPDB Validation 3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

Structural analysis of NSAID binding by prostaglandin H2 synthase: time-dependent and time-independent inhibitors elicit identical enzyme conformations.

Selinsky, B.S.Gupta, K.Sharkey, C.T.Loll, P.J.

(2001) Biochemistry 40: 5172-5180

  • DOI: 10.1021/bi010045s
  • Primary Citation of Related Structures:  
    1EQH, 1EQG, 1HT8, 1HT5

  • PubMed Abstract: 
  • Nonsteroidal antiinflammatory drugs (NSAIDs) block prostanoid biosynthesis by inhibiting prostaglandin H(2) synthase (EC 1.14.99.1). NSAIDs are either rapidly reversible competitive inhibitors or slow tight-binding inhibitors of this enzyme. These different modes of inhibition correlate with clinically important differences in isoform selectivity ...

    Nonsteroidal antiinflammatory drugs (NSAIDs) block prostanoid biosynthesis by inhibiting prostaglandin H(2) synthase (EC 1.14.99.1). NSAIDs are either rapidly reversible competitive inhibitors or slow tight-binding inhibitors of this enzyme. These different modes of inhibition correlate with clinically important differences in isoform selectivity. Hypotheses have been advanced to explain the different inhibition kinetics, but no structural data have been available to test them. We present here crystal structures of prostaglandin H(2) synthase-1 in complex with the inhibitors ibuprofen, methyl flurbiprofen, flurbiprofen, and alclofenac at resolutions ranging from 2.6 to 2.75 A. These structures allow direct comparison of enzyme complexes with reversible competitive inhibitors (ibuprofen and methyl flurbiprofen) and slow tight-binding inhibitors (alclofenac and flurbiprofen). The four inhibitors bind to the same site and adopt similar conformations. In all four complexes, the enzyme structure is essentially unchanged, exhibiting only minimal differences in the inhibitor binding site. These results argue strongly against hypotheses that explain the difference between slow tight-binding and fast reversible competitive inhibition by invoking global conformational differences or different inhibitor binding sites. Instead, they suggest that the different apparent modes of NSAID binding may result from differences in the speed and efficiency with which inhibitors can perturb the hydrogen bonding network around Arg-120 and Tyr-355.


    Organizational Affiliation

    Department of Chemistry, Villanova University, Pennsylvania 19085, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PROSTAGLANDIN H2 SYNTHASE-1AB580Ovis ariesMutation(s): 0 
Gene Names: PTGS1COX1
EC: 1.14.99.1
Find proteins for P05979 (Ovis aries)
Explore P05979 
Go to UniProtKB:  P05979
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
BOG
Query on BOG

Download CCD File 
A, B
octyl beta-D-glucopyranoside
C14 H28 O6
HEGSGKPQLMEBJL-RKQHYHRCSA-N
 Ligand Interaction
NAG
Query on NAG

Download CCD File 
A, B
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
IBP
Query on IBP

Download CCD File 
A, B
IBUPROFEN
C13 H18 O2
HEFNNWSXXWATRW-JTQLQIEISA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
IBPIC50:  1060   nM  BindingDB
IBPKi:  5900   nM  BindingDB
IBPKi:  4800   nM  BindingDB
IBPIC50:  14400   nM  BindingDB
IBPIC50:  2600   nM  BindingDB
IBPIC50:  12000   nM  BindingDB
IBPIC50:  3000   nM  BindingDB
IBPIC50:  10100   nM  BindingDB
IBPIC50:  2260   nM  BindingDB
IBPIC50:  18000   nM  BindingDB
IBPIC50:  1860   nM  BindingDB
IBPIC50:  26000   nM  BindingDB
IBPIC50:  18000   nM  BindingDB
IBPIC50:  99   nM  BindingDB
IBPIC50:  13000   nM  BindingDB
IBPIC50:  25000   nM  BindingDB
IBPIC50:  1420   nM  BindingDB
IBPIC50:  1480   nM  BindingDB
IBPIC50:  72800   nM  BindingDB
IBPIC50:  4000   nM  BindingDB
IBPIC50:  3200   nM  BindingDB
IBPIC50:  3350   nM  BindingDB
IBPIC50:  10000   nM  BindingDB
IBPIC50:  2900   nM  BindingDB
IBPKi:  48   nM  BindingDB
IBPIC50:  11100   nM  BindingDB
IBPIC50:  9000   nM  BindingDB
IBPIC50:  6900   nM  BindingDB
IBPIC50:  7600   nM  BindingDB
IBPKi:  9000   nM  BindingDB
IBPIC50:  6300   nM  BindingDB
IBPKi:  7600   nM  BindingDB
IBPIC50:  290   nM  BindingDB
IBPIC50:  2900   nM  BindingDB
IBPIC50:  6300   nM  BindingDB
IBPIC50:  5000   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.223 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 98.65α = 90
b = 204.99β = 90
c = 221.96γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-04-11
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2018-01-31
    Changes: Advisory, Experimental preparation
  • Version 1.4: 2018-02-28
    Changes: Experimental preparation
  • Version 1.5: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary