Fig. 6: Thorarchaeota profilin interacts with polyproline.
From: Heimdallarchaea encodes profilin with eukaryotic-like actin regulation and polyproline binding
NMR monitored 1H–15N chemical shifts for the binding reaction of a fixed concentration of thorProfilin (200 μM) (a) and/or ΔN-thorProfilin (b) (200 μM) with different concentrations of polyproline from VASP (PPPAPPLPAAQ) respectively. The following VASP concentrations were used; 0 μM (blue), 5 mM (red), 7.0 mM (purple). c, d Expansions from (a) and (b) showing the shift of some interacting residues as the concentration of polyproline increases. The arrows in (c) indicate residues from the N-terminal extension interacting with polyproline. These residues are absent in the ΔN-thorProfilin as indicated with the green circle in (d). e, f Chemical shift plotted as a function of polyproline (VASP) concentration for a few residues for (e) thorProfilin and (f) ΔN-thorProfilin. The chemical shift was fitted to the equation describing the equilibrium interaction of two biomolecules as described above. The KD estimated from this fits range between 200–500 μM.
