1NTM

Crystal Structure of Mitochondrial Cytochrome bc1 Complex at 2.4 Angstrom


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.237 
  • R-Value Observed: 0.238 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis for the quinone reduction in the bc(1) complex: a comparative analysis of crystal structures of mitochondrial cytochrome bc(1) with bound substrate and inhibitors at the Q(i) site

Gao, X.Wen, X.Esser, L.Quinn, B.Yu, L.Yu, C.-A.Xia, D.

(2003) Biochemistry 42: 9067-9080

  • DOI: https://doi.org/10.1021/bi0341814
  • Primary Citation of Related Structures:  
    1NTK, 1NTM, 1NTZ, 1NU1

  • PubMed Abstract: 

    Cytochrome bc(1) is an integral membrane protein complex essential to cellular respiration and photosynthesis. The Q cycle reaction mechanism of bc(1) postulates a separated quinone reduction (Q(i)) and quinol oxidation (Q(o)) site. In a complete catalytic cycle, a quinone molecule at the Q(i) site receives two electrons from the b(H) heme and two protons from the negative side of the membrane; this process is specifically inhibited by antimycin A and NQNO. The structures of bovine mitochondrial bc(1) in the presence or absence of bound substrate ubiquinone and with either the bound antimycin A(1) or NQNO were determined and refined. A ubiquinone with its first two isoprenoid repeats and an antimycin A(1) were identified in the Q(i) pocket of the substrate and inhibitor bound structures, respectively; the NQNO, on the other hand, was identified in both Q(i) and Q(o) pockets in the inhibitor complex. The two inhibitors occupied different portions of the Q(i) pocket and competed with substrate for binding. In the Q(o) pocket, the NQNO behaves similarly to stigmatellin, inducing an iron-sulfur protein conformational arrest. Extensive binding interactions and conformational adjustments of residues lining the Q(i) pocket provide a structural basis for the high affinity binding of antimycin A and for phenotypes of inhibitor resistance. A two-water-mediated ubiquinone protonation mechanism is proposed involving three Q(i) site residues His(201), Lys(227), and Asp(228).


  • Organizational Affiliation

    Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex core protein I, mitochondrial446Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex core protein 2, mitochondrial439Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
UniProt
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Cytochrome b379Bos taurusMutation(s): 0 
Membrane Entity: Yes 
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
cytochrome c1241Bos taurusMutation(s): 0 
Membrane Entity: Yes 
UniProt
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Entity ID: 5
MoleculeChains Sequence LengthOrganismDetailsImage
UBIQUINOL-CYTOCHROME C REDUCTASE IRON-SULFUR SUBUNIT, mitochondrial196Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
UniProt
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Entity ID: 6
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex 14 kDa protein110Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
UniProt
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Entity ID: 7
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex ubiquinone-binding protein QP-C81Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
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Entity ID: 8
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex 11 kDa protein78Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
UniProt
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Entity ID: 9
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase 8 kDa protein57Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
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Entity ID: 10
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex 7.2 kDa protein62Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
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Entity ID: 11
MoleculeChains Sequence LengthOrganismDetailsImage
Ubiquinol-cytochrome C reductase complex 6.4 kDa protein56Bos taurusMutation(s): 0 
EC: 1.10.2.2
Membrane Entity: Yes 
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Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download Ideal Coordinates CCD File 
L [auth C],
M [auth C],
N [auth D]
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
FES
Query on FES

Download Ideal Coordinates CCD File 
O [auth E]FE2/S2 (INORGANIC) CLUSTER
Fe2 S2
NIXDOXVAJZFRNF-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.237 
  • R-Value Observed: 0.238 
  • Space Group: I 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 154.325α = 90
b = 154.325β = 90
c = 593.161γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-10-07
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance