Fig. 1: Architecture of the NOX2 core-Fab 7G5 complex.

a Cryo-EM map (left) and three-dimensional reconstruction (right) of the NOX2 core-Fab 7G5 complex viewed parallel to the membrane plane, with approximate membrane boundaries indicated in gray. b Cartoon topology model of the NOX2 core complex, with the membrane bilayer colored light gray. c Model of the NOX2 core (left) and cartoon representation of the transmembrane helices (right), viewed perpendicular to the membrane from the extracellular side. d Close-up view of the NOX2 TM core, with hemes (yellow) coordinated by conserved histidine residues (blue). The metal-to-metal distance between the two hemes is 19.8 Å, with a closest interatomic distance (vinyl-to-vinyl) of 7.4 Å. The putative reduction center, composed of His115 (blue) and His119, Arg54 (orange) is located close to the p7’ propionate group of the outer heme. Hydrophobic residues located between the two heme molecules, including Phe215, are highlighted in green.