Figure 7.

Sam35–Sam50 complex is sufficient for binding and assembly of β-barrel substrates. (A) Mitochondria (100 μg of total protein) isolated from wild-type (W303) cells transformed with YEplac195, Δsam37 cells transformed with YEplac195, and Δsam37 cells transformed with YEpSAM35 were solubilized in 1% digitonin buffer, and protein complexes were analyzed by BN-PAGE, blotted onto PVDF membranes, and immunodecorated with antisera against Sam50 and Sam35. (B) ³⁵S-labeled Tom40 precursor was incubated with mitochondria from the indicated strains for the indicated time at 25°C, and import was stopped by incubation on ice. Mitochondria were reisolated and solubilized with 0.8% digitonin buffer. Insoluble materials were pelleted, and protein complexes analyzed by BN-PAGE and digital autoradiography.