5-Carboxymethylaminomethyl-2-thiouridine or mcm5S2U, is a naturally occurring 2-thio-modification of tRNA catalyzed by the action of Nfs1 enzyme on cy-tRNALyS2UUU and cy-tRNAGlU3UUC
Definition
ChEBI: A thiouridine that is 2-thiouridine bearing an additional carboxymethylaminomethyl substituent at position 5 on the thiouracil ring.