Fig 1.

(a) Similarity of RoxA structure to that of cytochrome c peroxidase of Nitrosomonas europaea (NEP). An overlay of the central regions of RoxA (black) and NEP (gray), including the two heme centers and the interheme region, is shown. The heme axial amino acid ligands and the tryptophan residues, located in the middle between the two hemes (Trp302 in RoxA), are also shown. (b) Structure around the N-terminal heme center of RoxA. Phe317 is located in close proximity (4.95 Å) to the sixth coordination site of the heme iron.