eNOR
Ingroup eNOR sequences were identified by the presence of a conserved Gln residue in alignment position 333. This site distinguishes eNOR not only from other nitric oxide reductases, but also from members of the oxygen reductase superfamily, which have a conserved Tyr in this site that plays a role in cofactor crosslinking. (Hemp and Gennis, 2008) (Table S5). Outgroup sequences (oxygen reductase superfamily or other divergent nitric oxide reductases) were subsampled to a single taxon representative per major subgroup observed in a preliminary tree (Supplementary Datafile S4). Retained outgroup sequences CCQ74688.1, WP_100277903.1, WP_097280063.1, WP_089728124.1, RLC59399.1, and WP_083704903.1 are annotated as uncharacterized domains. Remaining sequences were re-aligned before tree construction, and manually rooted on the branch leading to the outgroup.