Human Heme Oxygenase Oxidation of alpha- and gamma-meso-phenylhemes

Experimental Data Snapshot

  • Resolution: 2.11 Å
  • R-Value Free: 0.310 
  • R-Value Work: 0.270 

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This is version 1.3 of the entry. See complete history


Human heme oxygenase oxidation of 5- and 15-phenylhemes.

Wang, J.Niemevz, F.Lad, L.Huang, L.Alvarez, D.E.Buldain, G.Poulos, T.L.Ortiz de Montellano, P.R.

(2004) J Biol Chem 279: 42593-42604

  • DOI: https://doi.org/10.1074/jbc.M406346200
  • Primary Citation of Related Structures:  
    1S13, 1T5P

  • PubMed Abstract: 

    Human heme oxygenase-1 (hHO-1) catalyzes the O2-dependent oxidation of heme to biliverdin, CO, and free iron. Previous work indicated that electrophilic addition of the terminal oxygen of the ferric hydroperoxo complex to the alpha-meso-carbon gives 5-hydroxyheme. Earlier efforts to block this reaction with a 5-methyl substituent failed, as the reaction still gave biliverdin IXalpha. Surprisingly, a 15-methyl substituent caused exclusive cleavage at the gamma-meso-rather than at the normal, unsubstituted alpha-meso-carbon. No CO was formed in these reactions, but the fragment cleaved from the porphyrin eluded identification. We report here that hHO-1 cleaves 5-phenylheme to biliverdin IXalpha and oxidizes 15-phenylheme at the alpha-meso position to give 10-phenylbiliverdin IXalpha. The fragment extruded in the oxidation of 5-phenylheme is benzoic acid, one oxygen of which comes from O2 and the other from water. The 2.29- and 2.11-A crystal structures of the hHO-1 complexes with 1- and 15-phenylheme, respectively, show clear electron density for both the 5- and 15-phenyl rings in both molecules of the asymmetric unit. The overall structure of 15-phenylheme-hHO-1 is similar to that of heme-hHO-1 except for small changes in distal residues 141-150 and in the proximal Lys18 and Lys22. In the 5-phenylheme-hHO-1 structure, the phenyl-substituted heme occupies the same position as heme in the heme-HO-1 complex but the 5-phenyl substituent disrupts the rigid hydrophobic wall of residues Met34, Phe214, and residues 26-42 near the alpha-meso carbon. The results provide independent support for an electrophilic oxidation mechanism and support a role for stereochemical control of the reaction regiospecificity.

  • Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143-2280, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heme oxygenase 1
A, B
233Homo sapiensMutation(s): 0 
Gene Names: HMOX1HO1HO
UniProt & NIH Common Fund Data Resources
Find proteins for P09601 (Homo sapiens)
Explore P09601 
Go to UniProtKB:  P09601
PHAROS:  P09601
GTEx:  ENSG00000100292 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP09601
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 1FH

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C40 H38 Fe N4 O4
Experimental Data & Validation

Experimental Data

  • Resolution: 2.11 Å
  • R-Value Free: 0.310 
  • R-Value Work: 0.270 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.914α = 90
b = 64.425β = 90.02
c = 60.467γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-08-24
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-23
    Changes: Data collection, Database references, Derived calculations, Refinement description