Fig. 2.

Ion cluster inversion in C94R/C99R eNOS. The upper panel demonstrates that wildtype eNOS contains a Zn₄ cluster with four negatively charged sulfur atoms surrounding the Zn²⁺ cation in a tetrahedral configuration. In the C94R/C99R mutant the introduction of four arginine residue are proposed to stabilize the dimeric interface of eNOS via electrostatic interactions with a ${\mathrm{PO}}_4^{3-}$ anion. The lower panel shows both the crystal structure of the Zn cluster (PDB ID 3NOS) in wildtype eNOS and computer simulated structure of the C94R/C99R mutant.