FIGURE 3.

ROP5 binds ATP in an unusual conformation. A, a stereo view of the pseudoactive site of ROP5B_I is shown comparing the ATP-bound (gray) and unbound (blue) structures. Residues that make contact with ATP are shown as sticks. The ATP and its associated Mg²⁺ and waters are superposed with the 1.72-Å 2F_o − F_c electron density map contoured at 2.5 σ. The PKA (B) and ROP5B_I (C) active sites are shown with bound ATP in an orientation to highlight the magnesium conformation. D, the ATP molecules bound to ROP5 (black) or PKA (green) have been overlaid to highlight triphosphate conformation.