Fig. 6: Illustration of the free-energy binding landscape of C5a binding to C5aR.

ΔGbu gives the free-energy difference between the ligand-bound and unbound states and is indicated for each binding site (binding site, effector site, and binding site + effector site) by vertical arrows. A positive allosteric interaction is measured when both binding sites (binding site and effector site) are occupied, as revealed by a significantly higher ΔGbu for the full binding of the C5a.