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Both ATP and an energized inner membrane are required to import a purified precursor protein into mitochondria.
Author(s) -
Eilers M.,
Oppliger W.,
Schatz G.
Publication year - 1987
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1987.tb04860.x
Subject(s) - chemiosmosis , inner mitochondrial membrane , mitochondrion , biochemistry , biology , cytochrome c oxidase , inner membrane , protein subunit , mitochondrial matrix , gtp' , atpase , atp synthase , cytosol , enzyme , gene
We have investigated the energy requirement of mitochondrial protein import with a simplified system containing only isolated yeast mitochondria, energy sources and a purified precursor protein. This precursor was a fusion protein composed of 22 residues of the cytochrome oxidase subunit IV pre‐sequence fused to mouse dihydrofolate reductase. Import of this protein required not only an energized inner membrane, but also ATP. ATP could be replaced by GTP, but not by CTP, TTP or non‐hydrolyzable ATP analogs. Added ATP did not increase the membrane potential of respiring mitochondria; it supported import even if the proton‐translocating mitochondrial ATPase and the entry of ATP into the matrix were blocked. We conclude that ATP exerts its effect on mitochondrial protein import outside the inner membrane.