Fig. 4: SpNOX displays a highly solvent-exposed outer heme and two putative oxygen-binding sites.
From: Structural and mechanistic insights into Streptococcus pneumoniae NADPH oxidase
a, SpNOX (cartoon representation, blue) presents an outer heme more solvent exposed than eukaryotic NOXs such as NOX2 (cyan; PDB 8GZ3)10 or DUOX1 (purple; PDB 7D3F)9 because of a lack of extracellular domains or large loops. b, Side view of the extracellular loops of SpNOX. c, Top view of SpNOX surface showing the solvent-exposed outer heme. d,e, Two different putative oxygen-reduction centers were identified in SpNOX, one formed by N84, N101 and Y105 (d), and another formed by H83 and S86 (e). The distance between the coordinated water molecules (red sphere and density) and the outer heme is shown as a black dashed line. Atoms within H-bond distance are marked with cyan dashed lines.
