Dissociation of import of the Rieske iron-sulfur protein into Saccharomyces cerevisiae mitochondria from proteolytic processing of the presequence.
The correlation between the import of the Rieske iron-sulfur protein into the mitochondrial matrix and processing of the precursor protein by matrix processing peptidase was investigated using high concentrations of metal chelators and iron-sulfur protein in which the recognition site for the matrix processing peptidase was destroyed by site-directed mutagenesis. High concentrations of EDTA and o-phenanthroline inhibit import of iron-sulfur protein into the matrix. The non-chelating structural isomers m-phenanthroline and p-phenanthroline inhibit import similar to o-phenanthroline, indicating that inhibition of import is mainly independent of the metal chelating ability of the compounds. Iron-sulfur protein in which the recognition site for the matrix processing peptidase had been destroyed by a point mutation was efficiently imported into the matrix space. Import of this mutant iron-sulfur protein was inhibited by the same concentrations of EDTA and o-phenanthroline which inhibit import of the wild-type protein. These results indicate that import of the iron-sulfur protein into the mitochondrial matrix is independent of proteolytic processing of the presequence, and that o-phenanthroline together with EDTA inhibits import of iron-sulfur protein into the matrix space of mitochondria by inhibiting a step other than proteolysis of the presequence.
Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
J H
JH
Nett
B L
BL
Trumpower
D001692:Biological Transport; D002413:Cations, Divalent; D002614:Chelating Agents; D004492:Edetic Acid / Q000494:pharmacology; D014450:Electron Transport Complex III; D006868:Hydrolysis; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D010618:Phenanthrolines / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*
D002413:Cations, Divalent; D002614:Chelating Agents; D007506:Iron-Sulfur Proteins; D010618:Phenanthrolines; C037989:Rieske iron-sulfur protein; D004492:Edetic Acid; D014450:Electron Transport Complex III; C025205:1,10-phenanthroline