FIGURE 1.

Bacterial A-type ISC proteins are functional orthologues of S. cerevisiae Isa1 but not of Isa2. A, S. cerevisiae strains isa1Δ and isa2Δ harboring p416-MET25 plasmids for the expression of E. coli IscA, SufA, or ErpA, each fused to the mitochondrial targeting sequence of the F₁-ATPase subunit β (F1β), were grown on SC minimal medium supplemented with glucose (SD) in the presence or absence of Glu and Lys. Cells harboring either the empty vector p416-MET25 (p416) or vectors containing yeast ISA1 or ISA2 genes were cultivated in parallel as a control. B, WT cells overproducing Isa1 and/or Isa2, as indicated, were grown in liquid SD medium. Cell extracts were prepared and subjected to immunoprecipitation (IP) with immobilized antibodies against Isa1 or Aco1. The immunoprecipitated material was analyzed by immunostaining with antibodies against Isa2.