Fig. S4.

Distribution of Group 5 [NiFe]-hydrogenases. The phylogenetic tree shows the phylogeny of the P. methylaliphatogenes hydrogenase large subunit sequence compared with those of Group 5 [NiFe]-hydrogenases. The tree was constructed using the neighbor-joining method, bootstrapped with 500 replicates, and rooted using representatives of the Group 1 and Group 2 [NiFe]-hydrogenases. Over 100 Group 5 [NiFe]-hydrogenases have been identified in the genomes of the dominant soil phyla Actinobacteria, Acidobacteria, Chloroflexi, Verrucomicrobia, Planctomycetes, and Proteobacteria.