Fig 2. Frequently occurring (i.e. present in at least 30% organisms) families of Fe-S proteins in aerobes and HC anaerobes.

(A): Venn diagram showing the distribution of the 116 frequently occurring Fe-S families within aerobes and HC anaerobes. (B), (C), and (D): Pie charts showing the types of Fe-S cluster (blue: Fe₂S₂; orange: Fe₄S₄; green: Fe₃S₄; yellow: two or more of Fe₂S₂-Fe₄S₄-Fe₃S₄; red: FeCys₄; grey: unknown type) associated with families conserved in aerobes (B), in anaerobes (D), and in both (C). (E), (F), and (G): histograms showing the number of families associated with specific functional processes in aerobes (E), in anaerobes (G), and in both (F). More than one functional process may be associated with a family. Unknown functional processes are excluded from the count.