Construction of fluorescent analogs to follow the uptake and distribution of cobalamin (vitamin B₁₂) in bacteria, worms, and plants

Vitamin B₁₂ is made by only certain prokaryotes yet is required by a number of eukaryotes such as mammals, fish, birds, worms, and Protista, including algae. There is still much to learn about how this nutrient is trafficked across the domains of life. Herein, we describe ways to make a number of different corrin analogs with fluorescent groups attached to the main tetrapyrrole-derived ring. A further range of analogs were also constructed by attaching similar fluorescent groups to the ribose ring of cobalamin, thereby generating a range of complete and incomplete corrinoids to follow uptake in bacteria, worms, and plants. By using these fluorescent derivatives we were able to demonstrate that Mycobacterium tuberculosis is able to acquire both cobyric acid and cobalamin analogs, that Caenorhabditis elegans takes up only the complete corrinoid, and that seedlings of higher plants such as Lepidium sativum are also able to transport B₁₂. Lawrence et al., employed chemical biology approaches to construct a range of fluorescent vitamin B₁₂ derivatives. They demonstrated that these fluorescent variants can be used to follow intracellular B₁₂ trafficking in bacteria, including E. coli and M. tuberculosis, the worm C. elegans, and a higher plant (Lepidium sativum).