Fig 3.

Cu-unresponsive mutants XJ3 and XJ11 contain CcoN in the absence of the CcoO and CcoP subunits of cbb₃-Cox. Membrane fractions (∼50 μg of total protein) of the wild-type (MT1131), ΔccoA (SE8), ΔccoNOQP (GK32), XJ3 (ccmA3), and XJ11 (ccmF11) strains grown under Ps or respiratory conditions in MPYE medium in the absence (−) or presence (+ Cu) of 5 μM Cu²⁺ were analyzed by 12.5% SDS-PAGE, and the CcoP (A), CcoO (A), and CcoN (B) subunits of cbb₃-Cox (indicated by arrows) were detected by respective antibodies against these subunits as described in Materials and Methods. The bands common to all lanes correspond to nonspecific proteins detected by the antibodies used.