Iron-Sulfur Cluster N2 of the Escherichia coli NADH:Ubiquinone Oxidoreductase (Complex I) Is Located on Subunit NuoB

The proton-pumping NADH:ubiquinone oxidoreductase, also called respiratory complex I, couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. One FMN and up to 9 iron-sulfur (Fe/S) clusters participate in the redox reaction. There is discussio...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2003-11, Vol.278 (48), p.47602-47609
Main Authors: Flemming, Dirk, Schlitt, Angela, Spehr, Volker, Bischof, Tobias, Friedrich, Thorsten
Format: Article
Language:English
Subjects:
Amino Acid Motifs
Amino Acid Sequence
Blotting, Western
Cell Division
Cysteine - chemistry
Electron Spin Resonance Spectroscopy
Electron Transport Complex I - chemistry
Escherichia coli
Escherichia coli - enzymology
Escherichia coli - metabolism
Escherichia coli Proteins - chemistry
Ferredoxins - chemistry
Gene Deletion
Genetic Vectors
Iron-Sulfur Proteins - chemistry
Ligands
Magnetics
Molecular Sequence Data
Mutagenesis, Site-Directed
Mutation
NADH, NADPH Oxidoreductases - chemistry
NADP - chemistry
NuoA protein
NuoB protein
NuoI protein
Oxidation-Reduction
Peptides - chemistry
Protons
Sequence Homology, Amino Acid
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The proton-pumping NADH:ubiquinone oxidoreductase, also called respiratory complex I, couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. One FMN and up to 9 iron-sulfur (Fe/S) clusters participate in the redox reaction. There is discussion that the EPR-detectable Fe/S cluster N2 is involved in proton pumping. However, the assignment of this cluster to a distinct subunit of the complex as well as the number of Fe/S clusters giving rise to the EPR signal are still under debate. Complex I from Escherichia coli consists of 13 polypetides called NuoA to N. Either subunit NuoB or NuoI could harbor Fe/S cluster N2. Whereas NuoB contains a unique motif for the binding of one Fe/S cluster, NuoI contains a typical ferredoxin motif for the binding of two Fe/S clusters. Individual mutation of all four conserved cysteine residues in NuoB resulted in a loss of complex I activity and of the EPR signal of N2 in the cytoplasmic membrane as well as in the isolated complex. Individual mutations of all eight conserved cysteine residues of NuoI revealed a variable phenotype. Whereas cluster N2 was lost in most NuoI mutants, it was still present in the cytoplasmic membranes of the mutants NuoI C63A and NuoI C102A. N2 was also detected in the complex isolated from the mutant NuoI C102A. From this we conclude that the Fe/S cluster N2 is located on subunit NuoB.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M308967200