Arg410 near the Heme Proximal Ligand of Neuronal Nitric Oxide Synthase Is Critical for Both Substrate Recognition and Electron Transfer

Mutations at a well-conserved Arg410 located near the heme proximal axial ligand in the oxygenase domain of neuronal NOS (nNOS) abolished both substrate recognition and electron transfer to the heme, suggesting that this residue plays an important role in the architecture of the substrate recognition site and the electron transfer process.