Fig. 9

Structures of the known families of laterally open helical protein-conducting channels. Top: Structural models shown as solvent-excluded surfaces colour-coded by hydropathy. The hydropathy of the lipidic and aqueous phases represented on a separate scale, ranging from hydrophilic (white) to hydrophobic (grey). White circles indicate intramembrane hydrophilic grooves. Middle: models shown as tubes colour-coded by position. Transmembrane segments in the vicinity of the hydrophilic groove are numbered. Bottom: Axial views of each molecule showing only transmembrane helices. From left to right, the models representing each family are as follows. Rhomboid: S. cerevisiae Der1 (6vjz), Hrd1: S. cerevisiae Hrd1 (6vjz), YidC: M. jannaschii MJ0480 (predicted, see Additional file 2: Figure S4), Tim17: S. cerevisiae Tim22 (6lo8, [117]), TatC: Aquifex aeolicus TatC (4b4a, [52])