Figure 7.

Insertion of OEP7 into liposomes lacking PG, PI, or SL. Insertion of [³⁵S]methionine-labeled OEP7 into liposomes (A) was performed as described with the use of liposomes of standard lipid composition lacking PG (lanes 2–4), PI (lanes 6–8), and SL (lanes 10–12). After competition with N-liposomes (lanes 2, 6, and 10) S-liposomes where treated with thermolysin in the absence (lanes 3, 7, and 11; Thr) or presence of 1% (vol/vol) Triton X-100 (lanes 4, 8, and 12; 1% TX-100). Lanes 1, 5, and 9 show 10% translation product (TP) used for insertion. A model of the orientation of OEP7 within the different bilayers is shown in B. In C, the amount of [³⁵S]methionine-labeled OEP7 bound to liposomes of various lipid compositions was quantified and the results of three independent experiments were averaged. The total amount of bound protein to liposomes of standard lipid composition was set to 100% for comparison. In D, preSSU (10% shown in lane 1) association with liposomes composed of outer envelope lipids (lane 2), an isolated lipid mixture with standard composition (lane 3), without MGDG (lane 4), without DGDG (lane 5), without PG (lane 6), with increased PC content (lane 7), and without PI/SL (lane 8) is shown.