Figure 4

Biophysical characterization of Furamidine-cTnC interaction. (a) ITC for titration of Furamidine into cTnC. Insert: Measured steady-state dissociation constants. (b) ITC titration of unmodified cTnI_AR into cTnC in the absence (left) and in the presence of Furamidine (middle). Measured steady-state dissociation constants are shown on the right. (c) Top: Part of 2D-¹H-¹⁵N HSQC spectrum of cTnC in the absence (blue) and in the presence (purple) of Furamidine. Bottom: Plot of chemical shift perturbations (∆δ) of cTnC after addition of excess Furamidine. (d) Top: Chemical shift perturbations mapped onto cTnC structure with the same colour coding as shown in (c). Bottom: Docking pose for Furamidine (green) binding to CcTnC (grey, surface representation) using flexible docking in AutoDock Vina. The position of cTnI_AR (cyan) in the cardiac troponin complex (PDB 1J1D) was superimposed onto the structure. Means ± SEM, n=3. Statistical significance between control and drug treatment was assessed with an unpaired two-tailed student’s t-test: **p<0.01.