eNOR
A preliminary alignment for the eNOR gene showed a poorly conserved region near the C-terminal end of the ORF (see Table S4); to improve accuracy and avoid misalignment, this region was manually removed, and the remaining sequences were realigned prior to tree construction. Two sequences (Actinobacteria bacterium RBG_16_68_12, OFW73639.1, and Thermus WP_015717644.1) with missing N-terminal regions and three sequences (Chloroflexi bacterium, RME47896.1; Rhodocyclaceae bacterium UTPRO2, OQY7467.1; and Rhodothermus profundi , WP_072715415.1) with missing C-terminal regions were included in the final alignment; the placement of these sequences is therefore based upon fewer alignment sites than other taxa. All retain key active site residues and show no clear evidence of long branch attraction artifacts in the tree.