Figure 3.

FAF has twice the drug loading capacity compared to FSI and FA. Isothermal titration calorimetry was used to quantify the binding stoichiometry and thermodynamic parameters between Rapa (8 µM) in 2.4% v/v DMSO in PBS at 37 °C against increasing titrations of (a) FSI, (b) FA and (c) FAF. An inflection in the ELP/Rapa ratio was ~1 for FSI and FA and ~0.5 for FAF, which is roughly consistent with having 1 (FA, FSI) or 2 (FAF) FKBP domains per ELP. A representative data set is shown from n = 3 per group.