Fig 2.

c-type cytochrome profiles of Cu-unresponsive mutants XJ3 and XJ11. (A) Membrane fractions (∼50 μg of total protein) of the wild-type (MT1131), ΔccoA (SE8), ΔccoNOQP (GK32), XJ3 (ccmA3), and XJ11 (ccmF11) strains grown under respiratory conditions in MPYE medium in the absence or presence (+ Cu) of 5 μM Cu²⁺ were analyzed by 16.5% SDS-PAGE, and the c-type cytochromes were revealed by TMBZ staining as described in Materials and Methods. (B) Chromatophore supernatants (∼100 μg of total protein) containing soluble cytochrome c₂ of the wild-type (MT1131), XJ3 (ccmA3), and XJ11 (ccmF11) strains grown under respiratory conditions in MPYE medium in the absence (−) or presence (+) of 5 μM Cu²⁺ were analyzed by 18% SDS-PAGE, and the c-type cytochromes were revealed as described for panel A. (C) Membrane fractions (∼50 μg of total protein) of the wild-type (MT1131), ΔccoA (SE8), Δbc₁ (MT-RBC1 lacking cytochrome bc₁), XJ3 (ccmA3), and XJ11 (ccmF11) strains grown under photosynthetic (Ps) or respiratory conditions in MPYE medium in the absence (−) or presence (+) of 5 μM Cu²⁺ were analyzed by 12.5% SDS-PAGE, and the cytochrome c₁ subunit of cytochrome bc₁ was detected by specific antibodies as described in Materials and Methods.