2BS2: Quinol:fumarate Reductase From Wolinella Succinogenes

Citation:
Abstract
Membrane protein complexes can support both the generation and utilisation of a transmembrane electrochemical proton potential ('proton-motive force'), either by transmembrane electron transfer coupled to protolytic reactions on opposite sides of the membrane or by transmembrane proton transfer. Here we provide the first evidence that both of these mechanisms are combined in the case of a specific respiratory membrane protein complex, the dihaem-containing quinol:fumarate reductase (QFR) of Wolinella succinogenes, so as to facilitate transmembrane electron transfer by transmembrane proton transfer. We also demonstrate the non-functionality of this novel transmembrane proton transfer pathway ('E-pathway') in a variant QFR where a key glutamate residue has been replaced. The 'E-pathway', discussed on the basis of the 1.78-Angstrom-resolution crystal structure of QFR, can be concluded to be essential also for the viability of pathogenic epsilon-proteobacteria such as Helicobacter pylori and is possibly relevant to proton transfer in other dihaem-containing membrane proteins, performing very different physiological functions.
PDB ID: 2BS2Download
MMDB ID: 41933
PDB Deposition Date: 2005/5/14
Updated in MMDB: 2006/12
Experimental Method:
x-ray diffraction
Resolution: 1.78  Å
Source Organism:
Similar Structures:
Biological Unit for 2BS2: hexameric; determined by author and by software (PQS)
Molecular Components in 2BS2
Label Count Molecule
Proteins (6 molecules)
2
Quinol-fumarate Reductase Flavoprotein Subunit a
Molecule annotation
2
Quinol-fumarate Reductase Iron-sulfur Subunit B
Molecule annotation
2
Quinol-fumarate Reductase Diheme Cytochrome B Subunit C
Molecule annotation
Chemicals (18 molecules)
1
2
2
2
3
2
4
2
5
2
6
2
7
4
8
2
* Click molecule labels to explore molecular sequence information.

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