FIG. 2.

Crystal structure of GDP-bound RhoA. In the GDP-bound form of Rho, the Mg²⁺ ion is coordinated by the β phosphate group of GDP and a water molecule that interacts with T37 for stabilization. The OH group of T37 is glucosylated by the large clostridial toxins, inactivating this regulatory protein. The region involved in substrate specificity is in purple and includes residues 24 to 29 (22 to 27 in Rac and Cdc42). This figure was generated and rendered with PyMOL (34).