Construction of Fluorescent Analogs to Follow the Uptake and Distribution of Cobalamin (Vitamin B12) in Bacteria, Worms, and Plants

Abstract

Vitamin B 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 B.

Does a Conjugation Site Affect Transport of Vitamin B12–Peptide Nucleic Acid Conjugates into Bacterial Cells?

“…Hence, incomplete corrinoid 32 can also be successfully applied as a transporter, if a sufficiently high amount of the conjugate is applied. As suggested by Warren et al., the requirement for a higher concentration of incomplete corrinoid may be because it exhibits poorer molecular recognition through the uptake mechanism. Whereas for conjugates 25 and 26 the decrease in the level of fluorescence remains at the same level, for concentrations higher than 1 μ m , the effect varies for Cbl derivatives functionalized at other positions.…”

“…Certain microorganisms exhibit diversified requirements for this nutrient; some are capable of synthesizing this molecule (either de novo or from its precursors; in this regard, they are a source of Cbl for certain eukaryotes), whereas others do not need it . There are also microorganisms ( Escherichia coli , Mycobacterium tuberculosis , Salmonella Typhimurium) that, similarly to mammals, develop a number of receptors responsible for the recognition of Cbl and its subsequent internalization . As a consequence, we envisage that these pathways may also be utilized to transport cargoes into bacterial cells.…”

“…Vitamin B 12 (cobalamin (Cbl);F igure 1) is essential for proper functioning of mammals. [1][2][3] As an endogenous compound, it reachesm ammalian cells by au nique dietary pathway that can be used for the delivery of cargoes of interesti nto cells.…”

“…[1][2][3] As an endogenous compound, it reachesm ammalian cells by au nique dietary pathway that can be used for the delivery of cargoes of interesti nto cells. [4,5] Exampleso ft his approach encompass vitamin B 12 conjugates with therapeutics (including proteins [6,7] and anticancer drugs), [8,9] as well as fluorescent [10][11][12] and radioisotope labels. [13,14] Certain microorganisms exhibit diversified requirements for this nutrient;s ome are capable of synthesizing this molecule (either de novo or from itsp recursors;i nt his regard, they are as ource of Cbl for certaine ukaryotes), [15] whereas others do not need it.…”

“…[16] There are also microorganisms (Escherichia coli, Mycobacterium tuberculosis, Salmonella Typhimurium) Figure 1. Representationsofvitamin B 12 (1)and cobinamide (2;full and truncated forms). Positions of interest are marked with blue circles.…”