Biogenesis of mitochondria. A requirement for mitochondrial protein synthesis for the formation of a normal adenine nucleotide transporter in yeast mitochondria

Abstract

1. Parameters of ATP uptake by fully functional Saccharomyces cerevisiae mitochondria, including kinetic constants, binding constants and sensitivity to atractylate, closely resemble those of mammalian mitochondria. Scatchard plots of atractylate-sensitive adenine nucleotide binding indicate two distinct sites of high affinity (binding constant, K(D)'=1mum), and low affinity (binding constant, K(D)''=20mum) in the ratio 1:3. Uptake has high Arrhenius activation energies (+35 and +57kJ/mol), above and below a transition temperature of 11 degrees C. Atractylate-insensitive ATP uptake is apparently not saturable and has a low Arrhenius activation energy (6kJ/mol), suggesting a non-specific binding process. 2. Kinetic and binding constants for ATP uptake are not significantly changed in catabolite-repressed or anaerobic mitochondrial structures. 3. Inhibition of the mitochondrial protein-synthesizing system by growth of cells in the presence of erythromycin, or loss of mitochondrial DNA by mutation profoundly alters the adenine nucleotide transporter. ATP uptake becomes completely insensitive to atractylate, and the high-affinity binding site is lost. However, the adenine nucleotide transporter does not appear to be totally eliminated, as a moderate amount of saturable low-affinity ATP binding remains. 4. It is concluded that products of the mitochondrial protein-synthesizing system, probably coded by mitochondrial DNA, are required for the normal function of the adenine nucleotide transporter.