FIGURE 4.
Requirement for anionic phospholipid for [3H]PDBu binding to the mutant C1 domains. The binding of [3H]PDBu to the mutant C1 domains was determined at constant total phospholipid (100 μg/ml) in which the proportion of phosphatidylserine in phosphatidylserine/phosphatidylcholine (PC) mixtures was varied as indicated. The concentration of [3H]PDBu for each mutant was adjusted to exceed the Kd for that mutant in 100% phosphatidylserine. Values were expressed relative to the binding in the presence of 100% phosphatidylserine. Data are the mean of triplicate experiments. Bars represent the mean; error bars represent ±S.E.