FIGURE 2.

Gene organization of the four butyrate production pathways in bacteria. The clustered genomic organization of four butyrate production pathways has been depicted. The text within the arrows shows the PFAM domain assignments corresponding to each gene in a pathway while the text above the arrow indicates the gene identifier for which PFAMs were used. Butyryl-CoA dehydrogenase (Bcd), the central enzyme in all four pathways, occurs in genomic context with the Pyruvate pathway genes and contains the dehydrogenase as well as Electron transferring α and β subunits. The final enzymes phosphate butyryl transferase (Ptb), butyrate kinase (Buk) and butyryl-CoA:acetate CoA transferase (But) occur on different locations in the bacterial genomes.