Fig. 2. Binding interactions between the individual phospholipids, detergent and stabilizing amino acid residues: (A) detergent (UM), (B) L1 (PC), (C) L2 (PE), (D) L3 (PI), (E) L4 (PE) and (F) L5 (CL). Apparent hydrogen bonds are indicated with black lines, and hydrophobic interactions with green semi-circles (see Materials and methods). Molecules are shown in ball-and-stick presentation using standard colors. They have been rearranged for clarity after flattening to a two-dimensional plane.