2GMJ

Structure of Porcine Electron Transfer Flavoprotein-Ubiquinone Oxidoreductase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Structure of electron transfer flavoprotein-ubiquinone oxidoreductase and electron transfer to the mitochondrial ubiquinone pool.

Zhang, J.Frerman, F.E.Kim, J.J.

(2006) Proc Natl Acad Sci U S A 103: 16212-16217

  • DOI: https://doi.org/10.1073/pnas.0604567103
  • Primary Citation of Related Structures:  
    2GMH, 2GMJ

  • PubMed Abstract: 

    Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a 4Fe4S flavoprotein located in the inner mitochondrial membrane. It catalyzes ubiquinone (UQ) reduction by ETF, linking oxidation of fatty acids and some amino acids to the mitochondrial respiratory chain. Deficiencies in ETF or ETF-QO result in multiple acyl-CoA dehydrogenase deficiency, a human metabolic disease. Crystal structures of ETF-QO with and without bound UQ were determined, and they are essentially identical. The molecule forms a single structural domain. Three functional regions bind FAD, the 4Fe4S cluster, and UQ and are closely packed and share structural elements, resulting in no discrete structural domains. The UQ-binding pocket consists mainly of hydrophobic residues, and UQ binding differs from that of other UQ-binding proteins. ETF-QO is a monotopic integral membrane protein. The putative membrane-binding surface contains an alpha-helix and a beta-hairpin, forming a hydrophobic plateau. The UQ-flavin distance (8.5 A) is shorter than the UQ-cluster distance (18.8 A), and the very similar redox potentials of FAD and the cluster strongly suggest that the flavin, not the cluster, transfers electrons to UQ. Two possible electron transfer paths can be envisioned. First, electrons from the ETF flavin semiquinone may enter the ETF-QO flavin one by one, followed by rapid equilibration with the cluster. Alternatively, electrons may enter via the cluster, followed by equilibration between centers. In both cases, when ETF-QO is reduced to a two-electron reduced state (one electron at each redox center), the enzyme is primed to reduce UQ to ubiquinol via FAD.


  • Organizational Affiliation

    Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Electron transfer flavoprotein-ubiquinone oxidoreductase
A, B
584Sus scrofaMutation(s): 0 
EC: 1.5.5.1
Membrane Entity: Yes 
UniProt
Find proteins for P55931 (Sus scrofa)
Explore P55931 
Go to UniProtKB:  P55931
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP55931
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
FAD
Query on FAD

Download Ideal Coordinates CCD File 
D [auth A],
J [auth B]
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
SF4
Query on SF4

Download Ideal Coordinates CCD File 
C [auth A],
I [auth B]
IRON/SULFUR CLUSTER
Fe4 S4
LJBDFODJNLIPKO-UHFFFAOYSA-N
TBU
Query on TBU

Download Ideal Coordinates CCD File 
E [auth A]
F [auth A]
G [auth A]
H [auth A]
K [auth B]
E [auth A],
F [auth A],
G [auth A],
H [auth A],
K [auth B],
L [auth B]
TERTIARY-BUTYL ALCOHOL
C4 H10 O
DKGAVHZHDRPRBM-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 
  • Space Group: P 4 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 154.839α = 90
b = 154.839β = 90
c = 130.199γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-10-17
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description