Interacting residues at key values of separation (r) in the PMF (shown by dashed lines in Figure 2).

Cut-off value is shortest inter-protomer contact distance less than 4.8 Å between any atoms, for representative structures from the different simulation windows indicated by the dashed lines. Bolded residues are those present in the crystallographic KOPr and MOPr structures at the same cut-off values. *The interaction with this residue comes from the palmitoyl chain of the C3.55, which is not present in the crystallographic structures. Italicized residues are mentioned specifically in the text.