Fig. 9.

Chemical structures of Zn²⁺–cyclen (2) (A) and Cu²⁺–cyclen (3) (B). (C) Surface representation of the crystal structure of GppNHp-bound H-Ras in complex with Zn²⁺–cyclen (PDB ID 3L8Y). The second binding site of Zn²⁺–cyclen is adjacent to loop 7 and the C-terminal helix α5. GppNHp and cyclen are depicted by sticks and Zn²⁺ by a green sphere. (D) Chemical structure of Zn²⁺–BPA (4).