Figure 4.

Fragmentation of riboflavin biosynthesis. (a) PP-cluster 211 contains the volatile part of riboflavin biosynthesis that is mostly missing in archaea (COGs 0307, 0117, 0807). (b) PP-cluster 220 contains the evolutionary most conservative part of the pathway (COGs 1985, 0108, 0054). Gray shading indicates enzymes in PP-cluster 220, unrelated to riboflavin biosynthesis.