Fig. 1
From: The archaeal-bacterial lipid divide, could a distinct lateral proton route hold the answer?
Schematic view of the proposed “inner lateral proton transfer” route (iLPT). Highlighted in different colors are the different layers of the membrane (from [10]), as indicated. The solvation layer of the lipid heads are represented as volume and protons as spheres. Carbonyl groups, present in bacteria and absent in archaea, are colored in pink. The movement of protons is indicated with arrows. An extended conformation of the lipids is depicted for illustrative purposes. The “outer lateral proton transfer” route is shown for comparison. PG, 1-palmitoyl-2-oleoyl phosphatidylglycerol; PC, 1-palmitoyl-2-oleoyl phosphatidylcholine; and APG, 2,3 diphytanyl archaetidylglycerol