Figure 2.

ORDs can bind two membranes simultaneously. (A) Dense, sucrose-loaded liposomes with the indicated lipid composition were incubated with light liposomes of identical lipid composition plus a trace amount of [³H]triolein (0.5 mM each) with and without purified ORD or BSA (0.4 µM) for 30 min at 30°C. Radioactivity in the supernatant after centrifugation was measured by scintillation counting. (B) Liposome pull-down assay performed as in A but with varying concentrations of Osh6p or Osh7p. (C) Turbidity assay (absorbance at 350 nm after 10 min) using 90 µM lipid and varying concentrations of Osh6p or BSA. (D) Time course of change in turbidity using 900 µM lipid and 0.4 µM Osh6p. Error bars indicate mean ± SEM (n = 3).