3B6H

Crystal structure of human prostacyclin synthase in complex with inhibitor minoxidil

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.62 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 

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This is version 1.2 of the entry. See complete history. 


Literature

Structures of Prostacyclin Synthase and Its Complexes with Substrate Analog and Inhibitor Reveal a Ligand-specific Heme Conformation Change

Li, Y.-C., Chiang, C.-W., Yeh, H.-C., Hsu, P.-Y., Whitby, F.G., Wang, L.-H., Chan, N.-L.

(2008) J Biol Chem 283: 2917-2926

  • DOI: 10.1074/jbc.M707470200
  • Primary Citation of Related Structures:  
    3B6H, 3B98, 3B99

  • PubMed Abstract: 

    • Prostacyclin synthase (PGIS) is a cytochrome P450 (P450) enzyme that catalyzes production of prostacyclin from prostaglandin H(2). PGIS is unusual in that it catalyzes an isomerization rather than a monooxygenation, which is typical of P450 enzymes. ...

    Prostacyclin synthase (PGIS) is a cytochrome P450 (P450) enzyme that catalyzes production of prostacyclin from prostaglandin H(2). PGIS is unusual in that it catalyzes an isomerization rather than a monooxygenation, which is typical of P450 enzymes. To understand the structural basis for prostacyclin biosynthesis in greater detail, we have determined the crystal structures of ligand-free, inhibitor (minoxidil)-bound and substrate analog U51605-bound PGIS. These structures demonstrate a stereo-specific substrate binding and suggest features of the enzyme that facilitate isomerization. Unlike most microsomal P450s, where large substrate-induced conformational changes take place at the distal side of the heme, conformational changes in PGIS are observed at the proximal side and in the heme itself. The conserved and extensive heme propionate-protein interactions seen in all other P450s, which are largely absent in the ligand-free PGIS, are recovered upon U51605 binding accompanied by water exclusion from the active site. In contrast, when minoxidil binds, the propionate-protein interactions are not recovered and water molecules are largely retained. These findings suggest that PGIS represents a divergent evolution of the P450 family, in which a heme barrier has evolved to ensure strict binding specificity for prostaglandin H(2), leading to a radical-mediated isomerization with high product fidelity. The U51605-bound structure also provides a view of the substrate entrance and product exit channels.

    Organizational Affiliation: 

    Institute of Biochemistry, College of Life Sciences, National Chung Hsing University, Taichung City 402, Taiwan.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Prostacyclin synthaseA, B498Homo sapiensMutation(s): 0 
Gene Names: PTGIS, CYP8, CYP8A1
EC: 5.3.99.4 (PDB Primary Data), 4.2.1.152 (UniProt)
Find proteins for Q16647 (Homo sapiens)
Explore Q16647 
Go to UniProtKB:  Q16647
NIH Common Fund Data Resources
PHAROS  Q16647
GTEx  ENSG00000124212
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM
Download Ideal Coordinates CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L		 Ligand Interaction
BOG
Query on BOG
Download Ideal Coordinates CCD File 
A, B
octyl beta-D-glucopyranoside
C14 H28 O6
HEGSGKPQLMEBJL-RKQHYHRCSA-N		 Ligand Interaction
MXD
Query on MXD
Download Ideal Coordinates CCD File 
A, B
6-PIPERIDIN-1-YLPYRIMIDINE-2,4-DIAMINE 3-OXIDE
C9 H15 N5 O
ZFMITUMMTDLWHR-UHFFFAOYSA-N		 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
MXDKd:  3400   nM  Binding MOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.62 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 68.762α = 90
b = 106.072β = 91.81
c = 73.901γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-11-20
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Database references, Derived calculations, Structure summary