Binding analysis of fluorescent PikAIII ACPdd to PikAIV KSdd-containing proteins measured by FP. a) FP assay design. 50 nM PikAIII ACPdd-FL was mixed with varying concentrations of KSdd, KSdd-KS-AT, or full module PikAIV, and allowed to equilibrate at room temperature before reading. b–c) KDs were calculated using a one site binding model, Y = Bmax*X / (KD + X). Dose response curves were performed in triplicate, and the error bars are SEM.