PDBsum entry 4g7p

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protein ligands links
Oxidoreductase PDB id
Jmol PyMol
Protein chain
213 a.a.
Waters ×135
PDB id:
Name: Oxidoreductase
Title: Rat heme oxygenase-1 in complex with heme and co with 1 hr illumination at 100 k: laser off
Structure: Heme oxygenase 1. Chain: a. Fragment: unp residues 1-267. Synonym: ho-1, hsp32. Engineered: yes
Source: Rattus norvegicus. Rat. Organism_taxid: 10116. Gene: hmox1. Expressed in: escherichia coli. Expression_system_taxid: 562.
1.90Å     R-factor:   0.168     R-free:   0.201
Authors: M.Sugishima,K.Moffat,M.Noguchi
Key ref: M.Sugishima et al. (2012). Discrimination between CO and O(2) in heme oxygenase: comparison of static structures and dynamic conformation changes following CO photolysis. Biochemistry, 51, 8554-8562. PubMed id: 23043644 DOI: 10.1021/bi301175x
20-Jul-12     Release date:   31-Oct-12    
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Protein chain
Pfam   ArchSchema ?
P06762  (HMOX1_RAT) -  Heme oxygenase 1
289 a.a.
213 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.  - Heme oxygenase (biliverdin-producing).
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Protoheme + 3 [reduced NADPH--hemoprotein reductase] + 3 O2 = biliverdin + Fe2+ + CO + 3 [oxidized NADPH--hemoprotein reductase] + 3 H2O
Bound ligand (Het Group name = HEM)
matches with 95.45% similarity
+ 3 × [reduced NADPH--hemoprotein reductase]
+ 3 × O(2)
= biliverdin
+ Fe(2+)
Bound ligand (Het Group name = CMO)
corresponds exactly
+ 3 × [oxidized NADPH--hemoprotein reductase]
+ 3 × H(2)O
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     membrane   10 terms 
  Biological process     intracellular signal transduction   49 terms 
  Biochemical function     signal transducer activity     9 terms  


DOI no: 10.1021/bi301175x Biochemistry 51:8554-8562 (2012)
PubMed id: 23043644  
Discrimination between CO and O(2) in heme oxygenase: comparison of static structures and dynamic conformation changes following CO photolysis.
M.Sugishima, K.Moffat, M.Noguchi.
Heme oxygenase (HO) catalyzes heme degradation, one of its products being carbon monoxide (CO). It is well known that CO has a higher affinity for heme iron than does molecular oxygen (O(2)); therefore, CO is potentially toxic. Because O(2) is required for the HO reaction, HO must discriminate effectively between CO and O(2) and thus escape product inhibition. Previously, we demonstrated large conformational changes in the heme-HO-1 complex upon CO binding that arise from steric hindrance between CO bound to the heme iron and Gly-139. However, we have not yet identified those changes that are specific to CO binding and do not occur upon O(2) binding. Here we determine the crystal structure of the O(2)-bound form at 1.8 Å resolution and reveal the structural changes that are specific to CO binding. Moreover, difference Fourier maps comparing the structures before and after CO photolysis at <160 K clearly show structural changes such as movement of the distal F-helix upon CO photolysis. No such changes are observed upon O(2) photolysis, consistent with the structures of the ligand-free, O(2)-bound, and CO-bound forms. Protein motions even at cryogenic temperatures imply that the CO-bound heme-HO-1 complex is severely constrained (as in ligand binding to the T-state of hemoglobin), indicating that CO binding to the heme-HO-1 complex is specifically inhibited by steric hindrance. The difference Fourier maps also suggest new routes for CO migration.