Figure 1.

Crystal structure of the trimer of BetP in complex with the lipid (PDB: 4C7R [36]). The individual protomers are shown as green, bright pink and blue ribbons. The lipids key in trimer formation are shown in sphere representation with yellow carbon atoms. The annular lipids bound to the periphery of the protein are shown in sphere representation with cyan carbon atoms. (A) The protein–lipid complex is shown from the intracellular side of the membrane. (B,C) The protein–lipid complex in two different views looking through the membrane to illustrate the different locations of the peripherally bound lipids.