1NTZ

Crystal Structure of Mitochondrial Cytochrome bc1 Complex Bound with Ubiquinone


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.247 

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: 10.1021/bi0341814
  • Primary Citation of Related Structures:  1NTK, 1NTM, 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 cat ...

    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

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex core protein I, mitochondrial
A
446Bos taurusGene Names: UQCRC1
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P31800 (Bos taurus)
Go to Gene View: UQCRC1
Go to UniProtKB:  P31800
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex core protein 2, mitochondrial
B
439Bos taurusGene Names: UQCRC2
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P23004 (Bos taurus)
Go to Gene View: UQCRC2
Go to UniProtKB:  P23004
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Cytochrome b
C
379Bos taurusGene Names: MT-CYB (COB, CYTB, MTCYB)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P00157 (Bos taurus)
Go to Gene View: MT-CYB
Go to UniProtKB:  P00157
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
cytochrome c1
D
241Bos taurusGene Names: CYC1
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P00125 (Bos taurus)
Go to Gene View: CYC1
Go to UniProtKB:  P00125
Entity ID: 5
MoleculeChainsSequence LengthOrganismDetails
UBIQUINOL-CYTOCHROME C REDUCTASE IRON-SULFUR SUBUNIT, mitochondrial
E
196Bos taurusGene Names: UQCRFS1
EC: 1.10.2.2
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P13272 (Bos taurus)
Go to Gene View: UQCRFS1
Go to UniProtKB:  P13272
Entity ID: 6
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex 14 kDa protein
F
110Bos taurusGene Names: UQCRB
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P00129 (Bos taurus)
Go to Gene View: UQCRB
Go to UniProtKB:  P00129
Entity ID: 7
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex ubiquinone-binding protein QP-C
G
81Bos taurusGene Names: UQCRQ
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P13271 (Bos taurus)
Go to Gene View: UQCRQ
Go to UniProtKB:  P13271
Entity ID: 8
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex 11 kDa protein
H
78Bos taurusGene Names: UQCRH
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P00126 (Bos taurus)
Go to Gene View: UQCRH
Go to UniProtKB:  P00126
Entity ID: 9
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase 8 kDa protein
I
57Bos taurusGene Names: UQCRFS1
EC: 1.10.2.2
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P13272 (Bos taurus)
Go to Gene View: UQCRFS1
Go to UniProtKB:  P13272
Entity ID: 10
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex 7.2 kDa protein
J
62Bos taurusGene Names: UQCR10
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P00130 (Bos taurus)
Go to Gene View: UQCR10
Go to UniProtKB:  P00130
Entity ID: 11
MoleculeChainsSequence LengthOrganismDetails
Ubiquinol-cytochrome C reductase complex 6.4 kDa protein
K
56Bos taurusGene Names: UQCR11 (UQCR)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Electron Transport Chain Complexes: Complex III (Cytochrome bc1)
Protein: 
Cytochrome bc1
Find proteins for P07552 (Bos taurus)
Go to Gene View: UQCR11
Go to UniProtKB:  P07552
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FES
Query on FES

Download SDF File 
Download CCD File 
E
FE2/S2 (INORGANIC) CLUSTER
Fe2 S2
NIXDOXVAJZFRNF-UHFFFAOYSA-N
 Ligand Interaction
HEM
Query on HEM

Download SDF File 
Download CCD File 
C, D
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
UQ2
Query on UQ2

Download SDF File 
Download CCD File 
C
UBIQUINONE-2
C19 H26 O4
SQQWBSBBCSFQGC-JLHYYAGUSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.247 
  • Space Group: I 41 2 2
Unit Cell:
Length (Å)Angle (°)
a = 153.828α = 90.00
b = 153.828β = 90.00
c = 596.671γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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