The iron-sulfur clusters in the two related forms of mitochondrial NADH: ubiquinone oxidoreductase made by Neurospora crassa.
Two related forms of the respiratory-chain complex, NADH: ubiquinone oxidoreductase (Complex I) are synthesized in the mitochondria of Neurospora crassa. Normally growing cells make a large, piericidin-A-sensitive form, which consists of some 23 different nuclear- and 6-7 mitochondrially encoded subunits. Cells grown in the presence of chloramphenicol make a small, piericidin-A-insensitive form which consists of only approximately 13 nuclear-encoded subunits. The subunits of the small form are either identical or similar to nuclear-encoded subunits of the large form. The iron-sulfur clusters in these two forms of Complex I are characterized by redox potentiometry and EPR spectroscopy. The large form of Complex I contains four EPR-detectable iron-sulfur clusters, N1, N2, N3 and N4, with the spin concentration of the individual clusters equivalent to the flavin concentration, similar to the mammalian counterparts. The small Complex I contains clusters N1, N3 and N4, but it is devoid of cluster N2. A model of the electron-transfer route through the large form of Complex I has been derived from these findings and an evolutionary pathway which leads to the emergence of large Complex I is discussed.
Wang
D C
DC
Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia 19104-6089.
Meinhardt
S W
SW
Sackmann
U
U
Weiss
H
H
Ohnishi
T
T
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology*; D008929:Mitochondria, Heart / Q000201:enzymology; D016660:NAD(P)H Dehydrogenase (Quinone); D009492:Neurospora crassa / Q000201:enzymology*; D010084:Oxidation-Reduction; D011199:Potentiometry; D011487:Protein Conformation; D011808:Quinone Reductases / Q000737:chemistry* / Q000378:metabolism
D007506:Iron-Sulfur Proteins; D046911:Macromolecular Substances; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases