Fig 7.

Lipid-facing residues in the hydrophobic core region drive spontaneous OMP insertion, (a) OMP insertion is described by 9 sequential discrete steps. The depth position (−4 to 4) up to where the TM region inserts into is regarded as the reaction coordinate, (b) Folding free energies of bacterial OMPs are approximated as the total transfer free energy of lipid-facing residues inserted into the bilayer (red line). The energetic barrier caused by the lipid-facing residues in the headgroup region (blue diamond) is compensated by the favorable folding free energy of the lipid-facing residues in the hydrophobic core (green circles).