Fig. 3: Genes inferred to be co-localized with those coding for methyl viologen-reducing (Group 3c) [NiFe]-hydrogenase (Mvh) and formate dehydrogenase (Fdh) in Type I and II MAGs (A) and the putative protein complexes they form to bifurcate electrons from H2 (B) or formate (C), respectively, to simultaneously reduce ferredoxin and heterodisulfide.

Percentages below each gene indicate amino acid identities between homologs encoded by Type I and Type II MAGs. In panels B and C, squares represent [4Fe-4S] clusters and triangles represent [2Fe-2S] clusters. CoB coenzyme B, CoM coenzyme M, FAD flavin adenine dinucleotide, Fd ferredoxin, Fdh formate dehydrogenase, Hdr heterodisulfide reductase, Mvh methyl viologen-reducing (Group 3c) hydrogenase. Figure modified from Thauer et al. [71] and Costa et al. [77].