2D0U

Crystal structure of cyanide bound form of human indoleamine 2,3-dioxygenase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.40 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.249 

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This is version 1.3 of the entry. See complete history


Literature

Crystal structure of human indoleamine 2,3-dioxygenase: catalytic mechanism of O2 incorporation by a heme-containing dioxygenase.

Sugimoto, H.Oda, S.Otsuki, T.Hino, T.Yoshida, T.Shiro, Y.

(2006) Proc Natl Acad Sci U S A 103: 2611-2616

  • DOI: 10.1073/pnas.0508996103
  • Primary Citation of Related Structures:  
    2D0U, 2D0T

  • PubMed Abstract: 
  • Human indoleamine 2,3-dioxygenase (IDO) catalyzes the cleavage of the pyrrol ring of L-Trp and incorporates both atoms of a molecule of oxygen (O2). Here we report on the x-ray crystal structure of human IDO, complexed with the ligand inhibitor 4-phenylimidazole and cyanide ...

    Human indoleamine 2,3-dioxygenase (IDO) catalyzes the cleavage of the pyrrol ring of L-Trp and incorporates both atoms of a molecule of oxygen (O2). Here we report on the x-ray crystal structure of human IDO, complexed with the ligand inhibitor 4-phenylimidazole and cyanide. The overall structure of IDO shows two alpha-helical domains with the heme between them. A264 of the flexible loop in the heme distal side is in close proximity to the iron. A mutant analysis shows that none of the polar amino acid residues in the distal heme pocket are essential for activity, suggesting that, unlike the heme-containing monooxygenases (i.e., peroxidase and cytochrome P450), no protein group of IDO is essential in dioxygen activation or proton abstraction. These characteristics of the IDO structure provide support for a reaction mechanism involving the abstraction of a proton from the substrate by iron-bound dioxygen. Inactive mutants (F226A, F227A, and R231A) retain substrate-binding affinity, and an electron density map reveals that 2-(N-cyclohexylamino)ethane sulfonic acid is bound to these residues, mimicking the substrate. These findings suggest that strict shape complementarities between the indole ring of the substrate and the protein side chains are required, not for binding, but, rather, to permit the interaction between the substrate and iron-bound dioxygen in the first step of the reaction. This study provides the structural basis for a heme-containing dioxygenase mechanism, a missing piece in our understanding of heme chemistry.


    Organizational Affiliation

    Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Indoleamine 2,3-dioxygenase AB406Homo sapiensMutation(s): 0 
Gene Names: IDO1IDOINDO
EC: 1.13.11.42 (PDB Primary Data), 1.13.11.52 (UniProt)
Find proteins for P14902 (Homo sapiens)
Explore P14902 
Go to UniProtKB:  P14902
NIH Common Fund Data Resources
PHAROS:  P14902
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.40 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.249 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.352α = 90
b = 97.089β = 90
c = 129.378γ = 90
Software Package:
Software NamePurpose
CNSrefinement
MAR345data collection
SCALEPACKdata scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-01-31
    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: 2017-10-11
    Changes: Refinement description