Figure 2.

Crystal structure of the P-Rex1 DEP1 domain. Although there is only one DEP1 chain per asymmetric unit, it crystallized as a double domain-swapped D₃ hexamer, in which each DEP1 chain contributes to three different protomers. A, top view of the DEP1 hexamer along the 3-fold symmetry axis. The unique DEP1 chain is colored with a gradient from its N (blue) to C (red) terminus. B, the hexamer rotated 90˚ around a vertical axis relative to A so the view is down the dihedral 2-fold axis. The unique DEP1 chain can be seen here contributing to the top left, then the bottom right, and finally the bottom left protomer. C, the unique chain of DEP1 from B with the approximate positions corresponding to the two domain swaps indicated. D, cartoon representation of the deconvoluted DEP1 structure, with domain-swapped loops indicated by dashed lines. Positively charged residues and Ser-436 in its polybasic β hairpin loop are shown with stick models for side chains. E, cartoon representation of P-Rex1 DEP2 domain from PDB entry 6PCV, which is the most closely related DEP domain structure to DEP1. It contains an extra helix at the C terminus.