Figure 4.

Phylogenetic tree of molybdopterin oxidoreductase catalytic subunits PsrA. Polysulfide reductase/thiosulfate reductase (Psr/Phs) clade is marked in yellow. Other abbreviations: arsenite oxidases (Aro); arsenate reductases (Arr); dimethylsulfoxide/trimethylamine-N-oxide reductases (DMSO/TMAO); formate dehydrogenases (Fdh); periplasmic nitrate reductases (Nap); membrane-bound nitrate/perchlorate reductases (Nar/Pcr); assimilatory nitrate reductases (Nas); tetrathionate reductases (Ttr); unknown reductases (Unk). Bacteria are highlighted in black, Crenarchaeota in blue, Euryarchaeota in green and Halobacteria in pink (see Supplementary Figure S6 for details).