title: Protein-protein interaction studies provide evidence for electron transfer from ferredoxin to lipoic acid synthase in Toxoplasma gondii.
abstract: The only known redox system in the apicoplast, a plastid-like organelle of apicomplexan parasites, is ferredoxin and ferredoxin-associated reductase. Ferredoxin donates electrons to different enzymes, presumably including lipoate synthase (LipA), which is essential for fatty acid biosynthesis. We recombinantly expressed and characterized LipA from the protozoan parasite Toxoplasma gondii, generated LipA-specific antibodies and confirmed the apicoplast localization of LipA. Electron transfer from ferredoxin to LipA would require direct protein-protein interaction. Such a robust interaction between the two proteins was demonstrated in both yeast and bacterial two-hybrid systems. Taken together, our results provide strong evidence for a role of ferredoxin as an electron donor to LipA.
authors.affiliation: FG16 Parasitologie, Robert Koch-Institut, 13353 Berlin, Germany.
authors.forename: Nora
authors.initials: N
authors.lastname: Frohnecke
authors.affiliation: FG16 Parasitologie, Robert Koch-Institut, 13353 Berlin, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Klein
authors.affiliation: FG16 Parasitologie, Robert Koch-Institut, 13353 Berlin, Germany. Electronic address: seeberf@rki.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Seeber
mesh_terms: D004579:Electron Transport / Q000502:physiology; D005288:Ferredoxins / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D013466:Sulfurtransferases / Q000235:genetics / Q000378:metabolism*; D014122:Toxoplasma / Q000235:genetics / Q000378:metabolism*
chemical_list: D005288:Ferredoxins; D015800:Protozoan Proteins; D013466:Sulfurtransferases; C116435:lipoic acid synthase
keywords: Apicomplexa; Ferredoxin; Lipoic acid synthesis; Plastid; Protein interactions; Two-hybrid system