title: The presence of the iron-sulfur protein (subunit V) of complex III in mitochondria of heme-deficient yeast cells lacking iron-sulfur clusters detectable by electron paramagnetic resonance.
abstract: The presence of subunit V, the iron-sulfur protein, of complex III has been demonstrated in mitochondria from a mutant of Saccharomyces cerevisiae which lacks 5-aminolevulinic acid synthase and, hence, is devoid of heme. The mature form (24 K Da) of the iron-sulfur protein was observed in equal amounts in the heme-deficient and heme-sufficient cells with antiserum against subunit V and either the sensitive immuno-transfer technique or immunoprecipitation from dodecylsulfate-solubilized mitochondria. In addition, a slight shoulder with a molecular mass 1.5 kDa larger than the mature form was present in mitochondria from the heme-deficient cells. Electron paramagnetic resonance spectroscopy revealed the absence of iron-sulfur signals due to clusters S-1, S-2 and S-3 of succinate dehydrogenase or to Rieske's iron-sulfur cluster of complex III in mitochondria from the heme-deficient cells. The lack of iron-sulfur centers in these cells may be a consequence of the absence of sulfite reductase in the cells without heme.
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D014450:Electron Transport Complex III; D005656:Fungal Proteins / Q000032:analysis*; D006418:Heme / Q000032:analysis; D007120:Immunochemistry; D007506:Iron-Sulfur Proteins / Q000032:analysis*; D008667:Metalloproteins / Q000032:analysis*; D008928:Mitochondria / Q000032:analysis*; D009097:Multienzyme Complexes / Q000032:analysis*; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis*; D011808:Quinone Reductases / Q000032:analysis*; D012441:Saccharomyces cerevisiae / Q000032:analysis* / Q000201:enzymology
chemical_list: D005656:Fungal Proteins; D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D009097:Multienzyme Complexes; D006418:Heme; D009247:NADH, NADPH Oxidoreductases; D011808:Quinone Reductases; D014450:Electron Transport Complex III