FIG 6 .

Phylogeny of NxrA from “Ca. Nitrotoga fabula” and related proteins. Consensus tree showing the alpha subunits of selected enzymes from the type II DMSO reductase family. Confirmed and putative (put.) NxrA and NarG proteins are indicated. Organisms or enrichment cultures with an observed nitrite-oxidizing phenotype are shown in orange, those with an observed nitrate-reducing phenotype are shown in purple. Pie charts indicate statistical support based on maximum likelihood (ML) (1,000 bootstrap iterations) and Bayesian inference (BI) (posterior probability, 10 independent chains). Numbers in wedges indicate the numbers of taxa. Abbreviations: ClrA, chlorate reductase; DdhA, dimethylsulfide dehydrogenase; EbdA, ethylbenzene dehydrogenase; PcrA, perchlorate reductase; SerA, selenate reductase. Bar, 0.01 estimated substitutions per residue.