Complex I (also known as NDH-1) is the most complicated and the most challenging enzyme of respiratory chain. It consists of up to 46 subunits in eukaryotes, from 14 subunits in most bacterial species investigated to date, and "only" 13 subunits in E. coli. The enzyme contains as cofactors 1 FMN and up to nine FeS clusters, binuclear and tetranuclear . The enzyme operates as a proton pump, i.e. it catalyses the transfer of protons across the membrane coupled with transfer of electrons from NADH to ubi- or menaquinone.
The scheme is based on literature data and partially resolved structure of Complex I from T. thermophilus (PDB entry 3M9S). Known locations of redox centers within subunits are indicated. Several subunits have been suggested to house quinone binding sites.
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biochemistry and biophysical studies relating to Complex
Verkhovskaya M, Knuuti, J., Wikström M. (2010) Role of Ca2+ in structure and function of Complex I
from Escherichia coli, Biochim. Biophys. Acta 1807, 36-41.
Euro L., Belevich G., Wikström M. and Verkhovskaya M. (2009)
High affinity cation-binding sites in Complex I from Escherichia coli.
Biochim Biophys Acta 1787, 1024-1028.
Belevich N., Verkhovskaya M., Verkhovsky M.I. (2009)
Chapter 4 Electron transfer in respiratory complexes resolved by an ultra-fast freeze-quench approach.
Methods Enzymol. 456, 75-93.
Euro L., Belevich G., Bloch D.,Verkhovsky M.I., Wikström M., Verkhovskaya M. (2009)
The role of the invariant glutamate 95 in the catalytic site of Complex I from Escherichia coli,
Biochim Biophys Acta 1787, 68-73
Euro L., Belevich G., Verkhovsky M.I., Wikström M., Verkhovskaya M. (2008)
Conserved lysine residues of the membrane subunit NuoM are involved in energy conversion by
the proton-pumping NADH:ubiquinone oxidoreductase (Complex I), Biochim Biophys Acta 1777, 1166-72
Euro L., Bloch D.A., Wikström M., Verkhovsky M.I., Verkhovskaya M. (2008)
Electrostatic interactions between FeS clusters in NADH:ubiquinone oxidoreductase (Complex I)
from Escherichia coli, Biochemistry 47, 3185-93
Verkhovskaya M.L., Belevich N., Euro L., Wikström M., Verkhovsky M.I. (2008)
Real-time electron transfer in respiratory complex I, Proc. Natl. Acad. Sci U. S. A 105, 3763-7
Belevich G., Euro L., Wikström M., and Verkhovskaya M. (2007) Role of the conserved
arginine 274 and histidine 224 and 228 residues in the NuoCD subunit of complex I from Escherichia coli,
Biochemistry 46, 526-33
Sinegina L., Wikström M., Verkhovsky M.I. and Verkhovskaya M. (2005) Activation of isolated
NADH:ubiquinone oxidoreductase I (Complex I) from Escherichia coli by detergent and phospholipids.
Recovery of ubiquinone reductase activity and changes in EPR signals of iron-sulfur clusters. Biochemistry