Fig. 1.

Structure of the substrate-free inward-facing conformation of Mhp1. (A) Cartoon representation as seen from a viewpoint along the membrane. Each of the longer helices (TMs 3, 5, 8, 10) that show a distinct curvature are each shown as two shorter helices broken in the middle. The cartoon has been coloured with the ‘bundle’ (TMs 1, 2, 6, 7) in red, the ‘hash motif’ (TMs 3, 4, 8, 9) in yellow, the ‘flexible helices’ (TMs 5, 10) in blue, the C-terminal helices in light grey and the small extracellular and cytoplasmic surface helices (IN 2-3, OUT 7-8) in darker grey. To orientate the reader the positions of the sodium and benzylhydantoin that are observed in the occluded structure (9) are represented by a light grey sphere and sticks, respectively. (B) As (A) but viewed from the inside of the cell. (C) Topology diagram coloured as above, illustrating the pseudo twofold repeat unit.