Crystal structure of the Alpha subunit PAS domain from soluble guanylyl cyclase

Soluble guanylate cyclase (sGC) is a heterodimeric heme protein of approximate to 150 kDa and the primary nitric oxide receptor. Binding of NO stimulates cyclase activity, leading to regulation of cardiovascular physiology and providing attractive opportunities for drug discovery. How sGC is stimulated and where candidate drugs bind remains unknown. The and sGC chains are each composed of Heme-Nitric Oxide Oxygen (H-NOX), Per-ARNT-Sim (PAS), coiled-coil and cyclase domains. Here, we present the crystal structure of the (1) PAS domain to 1.8 angstrom resolution. The structure reveals the binding surfaces of importance to heterodimer function, particularly with respect to regulating NO binding to heme in the (1) H-NOX domain. It also reveals a small internal cavity that may serve to bind ligands or participate in signal transduction. PDB Code(s): 4GJ4