Magnitude of energetic contributions to the shift in ln Keq from POPC to DOPC, SDPC, DOPE-Me2, DOPE-Me1, DOPE, and SDPE at a lipid/rhodopsin molar ratio of 250:1. (Shaded bars: ΔG0,L, membrane elastic energy; hatched bars: ΔG0,HB, energy from hydrogen bonding between PEs and rhodopsin; and ΔG0,HC, energy from direct interactions of sn-1 oleic acid chains and sn-2 DHA chains.