Figure 2.

(A) Aco1-α can complement a Δaco1 strain. Wild-type and Δaco1 strains harboring the indicated plasmids encoding aconitase-α hybrid protein (pAco1-α) or aconitase lacking the mitochondrial targeting sequence (pAco1-ΔSP) were grown on galactose medium plates. (B) Aconitase-specific activity. Wild-type and Δaco1 harboring the indicated plasmids were grown in galactose medium, and cell extracts were assayed for aconitase activity. (C) Processing of Aco1-α fusions. Aco1-α processing is blocked by inhibiting import into mitochondria with the proton ionophore CCCP. Wild-type and Δaco1 yeast strains induced for expression of Aco1-α were labeled with [³⁵S]methionine for 30 min, either in the absence (-) or presence (+) of 20 μM CCCP. Total cell extracts were prepared, immunoprecipitated with aconitase antiserum, and analyzed by SDS-PAGE. Dual arrows show positions of the precursor (P) and mature (M) proteins.