FIG 7.
Cosedimentation assay demonstrating the binding of occidiofungin to actin. (A) Binding curve of phalloidin to actin (Kd = 8 nM; the stoichiometry [ligand: protein] is 0.6:1.0). (B) Binding curve of occidiofungin to actin (Kd = 1 μM; the stoichiometry [ligand: protein] is 24:1). The graph is plotted between the amount of free occidiofungin obtained in the supernatant of the cosedimentation assay and the amount of bound occidiofungin obtained from the actin pellet. The data were fit to a standard Langmuir binding isotherm of the form: [X]bound = [X]×S/(Kd + [X]), where S is the maximal X bound, Kd is the dissociation constant, and X is the concentration of free ligand.