Figure 3.
Inhibition of the photoincorporation of [3H]promegestone into TAT-CRAC by promegestone and cholesterol. The TAT-CRAC peptide (160 μM) was incubated with [3H]promegestone in the presence or absence of increasing concentrations of promegestone (A) or cholesterol (B) and exposed to UV light as described in Materials and Methods. After crosslinking, the samples were separated by SDS/PAGE, and the radiolabeled peptides were detected by phosphorimaging. The crosslinking of [3H]promegestone to TAT-CRAC peptide is displaced by promegestone (A) and cholesterol (B). Relative intensity of the radiolabeled peptide was determined as indicated in Materials and Methods.