Eukaryotes iron-sulfur proteins

All these intermediates except for cytochrome c are membrane-associated (either in the mitochondrial inner membrane of eukaryotes or in the plasma membrane of prokaryotes). All three types of proteins involved in this chain— flavoproteins, cytochromes, and iron-sulfur proteins—possess electron-transferring prosthetic groups. 

Formate dehydrogenases are a diverse group of enzymes found in both prokaryotes and eukaryotes, capable of converting formate to CO2. Formate dehydrogenases from anaerobic microorganisms are, in most cases, Mo- or W- containing iron-sulfur proteins and additionally flavin or hemes. Selenium cysteine is a Mo- ligand. 

Although iron-sulfur proteins are found in various cellular localizations in eukaryotic cells, mitochondria are the major site of Fe-S cluster biosynthesis (Lill et ah, 1999). Deletions in nuclear genes involved in mitochondrial iron-sulfur cluster formation lead to massive accumulation of iron in mitochondria (Chapter 7). For example, deletion of ATM1, a mitochondrial ATPase, which seems to be responsible for the export of Fe-S clusters, leads to respiratory incompetence, excessive iron accumulation and leucine auxotrophy (Kispal et ah, 1999). In Ayfhl cells there is only partial loss of mitochondrial Fe-S enzymes and the cells are not leucine auxotrophs. 

Lill, R., Duftkiewitz, R., Elsasser, H.-R, Hausmann, A., Netz, D.J.A., Pierik, A.J., Stehling, O., Urzika, E. and Miihlenhoff, U. (2006) Mechanisms of iron-sulfur protein maturation in mitochondria, cytosol and nucleus of eukaryotes, Biochim. Biophys. Acta, 1763, 652-667. 

Lill, R. and Miihlenhoff, U. (2005) Iron-sulfur protein biogenesis in eukaryotes, TIBS, 30, 133-141. 

Lesniak J, Barton WA, Nikolov DB (2002) Structural and functional characterization of the Pseudomonas hydroperoxide resistance protein Ohr. EMBO J 21 6649-6659 Lesniak J, Barton WA, Nikolov DB (2003) Structural and functional features of the Escherichia coli hydroperoxide resistance protein OsmC. Protein Sci 12 2838-2843 Lill R, Kispal G (2000) Maturation of cellular Fe-S proteins an essential function of mitochondria. Trends Biochem Sci 25 352-356 Lill R, Miihlenhoff U (2005) Iron-sulfur protein biogenesis in eukaryotes. Trends Biochem Sci 30 133-141... 

Lill R, Miihlenhoff U (2006) Iron-sulfur protein biogenesis in eukaryotes components and mechanisms. Annu Rev Cell Dev Biol 22 457-486 Lindmark DG (1976) Acetate production by Tritrichomonas foetus. In Van den Bossche H (ed) Biochemistry of parasites and host-parasite relationships. Elsevier, Amsterdam, pp 15-21... 

Hausmann A, Aguilar Netz DJ, Balk J, Pierik AJ, Muhlenhoff U, Lill R (2005) The eukaryotic P loop NTPase NBP35 An essential component of the cytosolic and nuclear iron-sulfur protein assembly machinery. Proc Natl Acad Sci USA 102 3266-3271 Henriquez FL, Richards , Roberts F, McLeod R, Roberts CW (2005) The unusual mitochondrial compartment of Cryptosporidium parvum. Trends Parasitol 21 68-74 Horner DS, Foster PG, Embley TM (2000) Iron hydrogenases and the evolution of anaerobic eukaryotes. Mol Biol Evol 17 1695-1709... 

Law R, Hutson V (1992) Intracellular symbionts and the evolution of uniparental cytoplasmic inheritance. Proc Roy Soc Lond B Biol Sci 248 69-77 Lill R, Mfihlenhoff U (2005) Iron-sulfur-protein biogenesis in eukaryotes. Trends Biochem Sci 30 133-141... 

Thus both iron—sulfur proteins and SOD will continue to provide us with two metal proteins which span the anaerobic/aerobic and the prokaryote/eukaryote transitions in the development of plants and animals from bacteria and algae. 

Both groups of reactions are found in bacteria (14), all higher animals (i5), and plants (16) however, oxidative phosphorylation is responsible for 90 % of the oxygen consumed (i 7). Oxidative phosphorylation is driven by the respiratory electron-transport system that is embedded in the lipoprotein inner membrane of eukaryotic mitochondria and in the cell membrane of prokaryotes. It consists of four complexes (Scheme I). The first is composed of nicotinamide adenine dinucleotide (NADH) oxidase, flavin mononucleotide (FMN), and nonheme iron-sulfur proteins 18,19), and it transfers electrons from NADH to ubiquinone. The second is composed of succinate dehydrogenase (SDH), flavin adenine dinucleotide (FAD), and nonheme iron-sulfur proteins (20), and it transfers electrons from succinate to ubiquinone 21, 22). The third is composed of cytochromes b and c, and nonheme iron-sulfur proteins (23), and it transfers electrons from ubiquinone (UQ) to cytochrome c 24). The fourth complex consists of cytochrome c oxidase [ferrocytochrome c 0 oxidoreductase EC 1.9.3.1 25)] which transfers electrons from cytochrome c to O2 26, 27). 

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