1IGX

Crystal Structure of Eicosapentanoic Acid Bound in the Cyclooxygenase Channel of Prostaglandin Endoperoxide H Synthase-1.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.228 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history


Literature

Structure of eicosapentaenoic and linoleic acids in the cyclooxygenase site of prostaglandin endoperoxide H synthase-1.

Malkowski, M.G.Thuresson, E.D.Lakkides, K.M.Rieke, C.J.Micielli, R.Smith, W.L.Garavito, R.M.

(2001) J Biol Chem 276: 37547-37555

  • DOI: 10.1074/jbc.M105982200
  • Primary Citation of Related Structures:  
    1IGZ, 1IGX

  • PubMed Abstract: 
  • Prostaglandin endoperoxide H synthases-1 and -2 (PGHSs) can oxygenate 18-22 carbon polyunsaturated fatty acids, albeit with varying efficiencies. Here we report the crystal structures of eicosapentaenoic acid (EPA, 20:5 n-3) and linoleic acid (LA, 18:2 n-6) bound in the cyclooxygenase active site of Co(3+) protoporphyrin IX-reconstituted ovine PGHS-1 (Co(3+)-oPGHS-1) and compare the effects of active site substitutions on the rates of oxygenation of EPA, LA, and arachidonic acid (AA) ...

    Prostaglandin endoperoxide H synthases-1 and -2 (PGHSs) can oxygenate 18-22 carbon polyunsaturated fatty acids, albeit with varying efficiencies. Here we report the crystal structures of eicosapentaenoic acid (EPA, 20:5 n-3) and linoleic acid (LA, 18:2 n-6) bound in the cyclooxygenase active site of Co(3+) protoporphyrin IX-reconstituted ovine PGHS-1 (Co(3+)-oPGHS-1) and compare the effects of active site substitutions on the rates of oxygenation of EPA, LA, and arachidonic acid (AA). Both EPA and LA bind in the active site with orientations similar to those seen previously with AA and dihomo-gamma-linolenic acid (DHLA). For EPA, the presence of an additional double bond (C-17/C-18) causes this substrate to bind in a "strained" conformation in which C-13 is misaligned with respect to Tyr-385, the residue that abstracts hydrogen from substrate fatty acids. Presumably, this misalignment is responsible for the low rate of EPA oxygenation. For LA, the carboxyl half binds in a more extended configuration than AA, which results in positioning C-11 next to Tyr-385. Val-349 and Ser-530, recently identified as important determinants for efficient oxygenation of DHLA by PGHS-1, play similar roles in the oxygenation of EPA and LA. Approximately 750- and 175-fold reductions in the oxygenation efficiency of EPA and LA were observed with V349A oPGHS-1, compared with a 2-fold change for AA. Val-349 contacts C-2 and C-3 of EPA and C-4 of LA orienting the carboxyl halves of these substrates so that the omega-ends are aligned properly for hydrogen abstraction. An S530T substitution decreases the V(max)/K(m) of EPA and LA by 375- and 140-fold. Ser-530 makes six contacts with EPA and four with LA involving C-8 through C-16; these interactions influence the alignment of the substrate for hydrogen abstraction. Interestingly, replacement of Phe-205 increases the volume of the cyclooxygenase site allowing EPA to be oxygenated more efficiently than with native oPGHS-1.


    Related Citations: 
    • Mutational and X-ray Crystallographic analysis of the Interaction of Dihomo-Gamma-Linolenic Acid with Prostaglandin Endoperoxide H Synthases.
      Thuresson, E.D., Malkowski, M.G., Lakkides, K.M., Rieke, C.J., Mulichak, A.M., Ginell, S.L., Garavito, R.M., Smith, W.L.
      (2001) J Biol Chem 276: 10358
    • The Productive Conformation of Arachidonic Acid Bound to Prostaglandin Synthase.
      Malkowski, M.G., Ginell, S.L., Smith, W.L., Garavito, R.M.
      (2000) Science 289: 1933

    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Prostaglandin Endoperoxide H Synthase-1A576Ovis ariesMutation(s): 0 
Gene Names: PTGS1COX1
EC: 1.14.99.1
UniProt
Find proteins for P05979 (Ovis aries)
Explore P05979 
Go to UniProtKB:  P05979
Protein Feature View
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranoseB2N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G07375KG
GlyCosmos:  G07375KG
GlyGen:  G07375KG
Entity ID: 3
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
alpha-D-mannopyranose-(1-3)-beta-D-mannopyranose-(1-6)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranoseC5N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G30233OG
GlyCosmos:  G30233OG
GlyGen:  G30233OG
Entity ID: 4
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranoseD2N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G42666HT
GlyCosmos:  G42666HT
GlyGen:  G42666HT
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
COH
Query on COH

Download Ideal Coordinates CCD File 
H [auth A]PROTOPORPHYRIN IX CONTAINING CO
C34 H32 Co N4 O4
AQTFKGDWFRRIHR-CTESUSPADG
 Ligand Interaction
EPA
Query on EPA

Download Ideal Coordinates CCD File 
I [auth A]5,8,11,14,17-EICOSAPENTAENOIC ACID
C20 H30 O2
JAZBEHYOTPTENJ-JLNKQSITSA-N
 Ligand Interaction
BOG
Query on BOG

Download Ideal Coordinates CCD File 
E [auth A], G [auth A]octyl beta-D-glucopyranoside
C14 H28 O6
HEGSGKPQLMEBJL-RKQHYHRCSA-N
 Ligand Interaction
BGC
Query on BGC

Download Ideal Coordinates CCD File 
F [auth A]beta-D-glucopyranose
C6 H12 O6
WQZGKKKJIJFFOK-VFUOTHLCSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
EPAIC50:  13000   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.228 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 182.17α = 90
b = 182.17β = 90
c = 103.11γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-12-12
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary