1QLB: Respiratory Complex Ii-Like Fumarate Reductase From Wolinella Succinogenes

Citation:
Abstract
Fumarate reductase couples the reduction of fumarate to succinate to the oxidation of quinol to quinone, in a reaction opposite to that catalysed by the related complex II of the respiratory chain (succinate dehydrogenase). Here we describe the crystal structure at 2.2 A resolution of the three protein subunits containing fumarate reductase from the anaerobic bacterium Wolinella succinogenes. Subunit A contains the site of fumarate reduction and a covalently bound flavin adenine dinucleotide prosthetic group. Subunit B contains three iron-sulphur centres. The menaquinol-oxidizing subunit C consists of five membrane-spanning, primarily helical segments and binds two haem b molecules. On the basis of the structure, we propose a pathway of electron transfer from the dihaem cytochrome b to the site of fumarate reduction and a mechanism of fumarate reduction. The relative orientations of the soluble and membrane-embedded subunits of succinate:quinone oxidoreductases appear to be unique.
PDB ID: 1QLBDownload
MMDB ID: 14464
PDB Deposition Date: 1999/8/25
Updated in MMDB: 2000/12
Experimental Method:
x-ray diffraction
Resolution: 2.33  Å
Source Organism:
Similar Structures:
Biological Unit for 1QLB: hexameric; determined by software (PQS)
Molecular Components in 1QLB
Label Count Molecule
Proteins (6 molecules)
2
Fumarate Reductase Flavoprotein Subunit
Molecule annotation
2
Fumarate Reductase Iron-sulfur Protein
Molecule annotation
2
Fumarate Reductase Cytochrome B Subunit
Molecule annotation
Chemicals (18 molecules)
1
4
2
2
3
2
4
2
5
2
6
2
7
2
8
2
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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