Figure 7.

Sec62N but not Sec62N-ΔN10-ΔC40 is displaced from Sec63C by ribosomes. GST-Sec63C was immobilized on GSH-Sepharose. Sec62N (lanes 2–5) or Sec62N-ΔN10-ΔC40 (lanes 7–10) were applied to the resin in the presence of BSA. After washing, the resin was eluted with phosphate buffer (3 mM KCl, 1 mM MgCl₂, 155 mM NaCl, 50 mM NaH₂PO₄, 200 mM Na₂HPO₄, pH 7.3, 0.65% CHAPS, 10 μg/ml BSA) or nontranslating ribosomes in phosphate buffer. After washing, the bound material was eluted and analyzed by SDS-PAGE followed by either protein staining (A) or Western blotting plus immunodetection with anti-penta-histidine antibodies (B).