Figure 1.

ThiS/MoaD/Ubiquitin-based protein conjugation system. The figure shows different themes by which a ThiS/MoaD/Ubiquitin-like polypeptide participates in thiamine biosynthesis, MoCo/WCo biosynthesis, and the ubiquitin conjugation/deconjugation system and the siderophore biosynthesis pathways. The '?' refers to the speculated part of the pathway inferred from operon organization. SUB refers to the polypeptide/protein substrate.