4E1G

X-ray crystal structure of alpha-linolenic acid bound to the cyclooxygenase channel of cyclooxygenase-2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.159 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Investigating Substrate Promiscuity in Cyclooxygenase-2: THE ROLE OF ARG-120 AND RESIDUES LINING THE HYDROPHOBIC GROOVE.

Vecchio, A.J.Orlando, B.J.Nandagiri, R.Malkowski, M.G.

(2012) J.Biol.Chem. 287: 24619-24630

  • DOI: 10.1074/jbc.M112.372243
  • Primary Citation of Related Structures:  3TZI

  • PubMed Abstract: 
  • The cyclooxygenases (COX-1 and COX-2) generate prostaglandin H(2) from arachidonic acid (AA). In its catalytically productive conformation, AA binds within the cyclooxygenase channel with its carboxylate near Arg-120 and Tyr-355 and ω-end located wit ...

    The cyclooxygenases (COX-1 and COX-2) generate prostaglandin H(2) from arachidonic acid (AA). In its catalytically productive conformation, AA binds within the cyclooxygenase channel with its carboxylate near Arg-120 and Tyr-355 and ω-end located within a hydrophobic groove above Ser-530. Although AA is the preferred substrate for both isoforms, COX-2 can oxygenate a broad spectrum of substrates. Mutational analyses have established that an interaction of the carboxylate of AA with Arg-120 is required for high affinity binding by COX-1 but not COX-2, suggesting that hydrophobic interactions between the ω-end of substrates and cyclooxygenase channel residues play a significant role in COX-2-mediated oxygenation. We used structure-function analyses to investigate the role that Arg-120 and residues lining the hydrophobic groove play in the binding and oxygenation of substrates by murine (mu) COX-2. Mutations to individual amino acids within the hydrophobic groove exhibited decreased rates of oxygenation toward AA with little effect on binding. R120A muCOX-2 oxygenated 18-carbon ω-6 and ω-3 substrates albeit at reduced rates, indicating that an interaction with Arg-120 is not required for catalysis. Structural determinations of Co(3+)-protoporphyrin IX-reconstituted muCOX-2 with α-linolenic acid and G533V muCOX-2 with AA indicate that proper bisallylic carbon alignment is the major determinant for efficient substrate oxygenation by COX-2. Overall, these findings implicate Arg-120 and hydrophobic groove residues as determinants that govern proper alignment of the bisallylic carbon below Tyr-385 for catalysis in COX-2 and confirm nuances between COX isoforms that explain substrate promiscuity.


    Organizational Affiliation

    Hauptman-Woodward Medical Research Institute and Department of Structural Biology, The State University of New York, Buffalo, New York 14203, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Prostaglandin G/H synthase 2
A, B
610Mus musculusGene Names: Ptgs2 (Cox-2, Cox2, Pghs-b, Tis10)
EC: 1.14.99.1
Find proteins for Q05769 (Mus musculus)
Go to UniProtKB:  Q05769
Small Molecules
Ligands 7 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MAN
Query on MAN

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A
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
COH
Query on COH

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A, B
PROTOPORPHYRIN IX CONTAINING CO
C34 H32 Co N4 O4
AQTFKGDWFRRIHR-CTESUSPADG
 Ligand Interaction
AKR
Query on AKR

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A
ACRYLIC ACID
C3 H4 O2
NIXOWILDQLNWCW-UHFFFAOYSA-N
 Ligand Interaction
EDO
Query on EDO

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A, B
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
LNL
Query on LNL

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A, B
ALPHA-LINOLENIC ACID
C18 H30 O2
DTOSIQBPPRVQHS-PDBXOOCHSA-N
 Ligand Interaction
NAG
Query on NAG

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A, B
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
BOG
Query on BOG

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A
B-OCTYLGLUCOSIDE
C14 H28 O6
HEGSGKPQLMEBJL-RKQHYHRCSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
LNLIC50: 12000 nM (86) BINDINGDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.159 
  • Space Group: I 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 120.378α = 90.00
b = 132.131β = 90.00
c = 180.438γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
Adxvdata processing
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-04-25
    Type: Initial release
  • Version 1.1: 2012-06-13
    Type: Database references
  • Version 1.2: 2012-08-01
    Type: Database references
  • Version 1.3: 2017-11-15
    Type: Refinement description