Fig. 2
From: The archaeal-bacterial lipid divide, could a distinct lateral proton route hold the answer?
Polar heads of different lipids used in [30, 31]. Similar polar groups are boxed with the same colors for comparison, positive groups in blue, glycerol in purple, phosphates in orange, glycerol-esters in red and hydrocarbon tails in orange. Lipids represented; PC, phosphatidyl choline; PE, phosphatidyl ethanolamine; PG, phosphatidyl glycerol; GMO, glycerol monooleate; PA, phosphatidic acid