PDBsum entry 4enw

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Oxidoreductase PDB id
Protein chains
726 a.a.
HDD ×4
Waters ×2752
PDB id:
Name: Oxidoreductase
Title: Structure of the s234n variant of e. Coli kate
Structure: Catalase hpii. Chain: a, b, c, d. Synonym: hydroxyperoxidase ii. Engineered: yes. Mutation: yes
Source: Escherichia coli. Organism_taxid: 83333. Strain: k12. Gene: b1732, jw1721, kate. Expressed in: escherichia coli. Expression_system_taxid: 562.
1.90Å     R-factor:   0.177     R-free:   0.221
Authors: P.C.Loewen,V.Jha
Key ref: V.Jha et al. (2012). Influence of main channel structure on H(2)O(2) access to the heme cavity of catalase KatE of Escherichia coli. Arch Biochem Biophys, 526, 54-59. PubMed id: 22820098 DOI: 10.1016/
13-Apr-12     Release date:   02-May-12    
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Protein chains
Pfam   ArchSchema ?
P21179  (CATE_ECOLI) -  Catalase HPII
753 a.a.
726 a.a.*
Key:    PfamA domain  PfamB domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Enzyme reactions 
   Enzyme class: E.C.  - Catalase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: 2 H2O2 = O2 + 2 H2O
2 × H(2)O(2)
= O(2)
+ 2 × H(2)O
      Cofactor: Heme; Mn(2+)
Bound ligand (Het Group name = HDD) matches with 93.33% similarity
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     cytoplasm   2 terms 
  Biological process     oxidation-reduction process   5 terms 
  Biochemical function     oxidoreductase activity     7 terms  


DOI no: 10.1016/ Arch Biochem Biophys 526:54-59 (2012)
PubMed id: 22820098  
Influence of main channel structure on H(2)O(2) access to the heme cavity of catalase KatE of Escherichia coli.
V.Jha, P.Chelikani, X.Carpena, I.Fita, P.C.Loewen.
The main channel for H(2)O(2) access to the heme cavity in large subunit catalases is twice as long as in small subunit catalases and is divided into two distinct parts. Like small subunit catalases, the 15Å of the channel adjacent to the heme has a predominantly hydrophobic surface with only weak water occupancy, but the next 15Å extending to the protein surface is hydrophilic and contains a complex water matrix in multiple passages. At the approximate junction of these two sections are a conserved serine and glutamate that are hydrogen bonded and associated with H(2)O(2) in inactive variants. Mutation of these residues changed the dimensions of the channel, both enlarging and constricting it, and also changed the solvent occupancy in the hydrophobic, inner section of the main channel. Despite these structural changes and the prominent location of the residues in the channel, the variants exhibited less than a 2-fold change in the k(cat) and apparent K(M) kinetic constants. These results reflect the importance of the complex multi-passage structure of the main channel. Surprisingly, mutation of either the serine or glutamate to an aliphatic side chain interfered with heme oxidation to heme d.