Fig. 2: Illustration of noble gas positions on the surfaces of the derivatised structures.

tmBR (a, argon; b, krypton), KR2-krypton (c), MAR-krypton (d). Each panel shows four orthogonal side views in the membrane. The hydrophobic membrane region is delimited with two black parallel lines. Krypton and argon atoms are shown as red and green spheres, respectively. Lipid fragments present in the derivatised structures are shown in sky-blue; lipid fragments from native structures are shown in orange for comparison. On the bottom of each panel four representative noble gas binding sites in each view are enlarged and the anomalous difference density krypton (red grid) or argon (green grid) are drawn at the 3.0 r.m.s. level. Symmetry-related molecules are shown in transparent dark to better illustrate the contacts.