5-Amino-6-(D-ribitylamino)uracil (5-A-RU) is a derivative of uracil and a precursor to riboflavin.1,2 It reacts non-enzymatically with dihydroxy acetone, methylglyoxal, or glyoxal to activate mucosal-associated invariant T (MAIT) cells isolated from iVα19-Tg and iVα19Vβ6-DTg mice.2 5-A-RU (100 nM, i.p.), when administered in combination with methylglyoxal, activates MAIT cells in iVα19 Cα-/--Tg mice. It is also a substrate for F0 synthase, an enzyme involved in the biosynthesis of the energy metabolism cofactor F420 in archaea, bacteria, and eukaryotes.1
References
1. Decamps, L., Philmus, B., Benjdia, A., et al. Biosynthesis of F0, precursor of the F420 cofactor, requires a unique two radical-SAM domain enzyme and tyrosine as substrate. J. Am. Chem. Soc. 134(44), 18173-18176 (2012).
2. Soudais, C., Samassa, F., Sarkis, M., et al. In vitro and in vivo analysis of the gram-negative bacteria-derived riboflavin precursor derivatives activating mouse MAIT cells. J. Immunol. 194(10), 4641-4649 (2015).