Figure 2. Crystal structure of the IFT80 protein.
(A) Structural overview showing the overall domain organization of CrIFT80. It contains two N-terminal β-propellers (coloured in red and orange) connected by a long strand and interacting with each other via several loops. A helical extension in β-propeller two keeps the C-terminal α-solenoid region (coloured in yellow) in position. (B) β-propeller one displays a canonical fold of a 7-bladed WD40 β-propeller. The most N-terminal β-strand forms the outermost strand of blade 7, effectively closing the ring-shaped structure by linking blade 7 to blade 1. Individual β-strands are numbered and the blade numbers are indicated in white circles. (C) β-propeller two displays an unusual open conformation where the incomplete blade seven lacks the outermost β-strand. Individual β-strands are numbered and the blade numbers are indicated in white circles. (D) Superpositioning of the CrIFT80 structure (coloured as in (A)) with the evolutionarily related β’COP protein (pdb: 3MKQ; coloured in grey). The two structures differ significantly with respect to the positions of β-propeller two as well as the α-solenoid C-terminus. (E) Isolated view on β-propeller 2 of β’COP (pdb:3MKQ, coloured in grey). Although this propeller also lacks the outermost strand in blade 7, it is closed by an extended loop in blade 1 (coloured in red).