Transferring groups other than aminoacyl groups
acetyl-CoA:tRNA uridine carboxymethyltransferase
acetyl-CoA + uridine34 in tRNA + S-adenosyl-L-methionine + H2O = CoA + 5-(carboxymethyl)uridine34 in tRNA + L-methionine + 5'-deoxyadenosine
uridine34 in tRNA;
5-(carboxymethyl)uridine34 in tRNA;
The enzyme, found in eukaryotes, most archaea, and some bacteria, catalyses the first step in modification of the wobble uridine base of certain tRNAs. In eukaryotes the enzyme is a complex of six conserved subunits, with ELP3 being the catalytic subunit. In archaea and bacteria the enzyme consists of a single subunit, homologous to ELP3. The enzyme contains an [4Fe-4S] cluster and uses radical chemistry. A 5'-deoxyadenosyl radical generated in the radical AdoMet (SAM) domain attacks the acetyl-CoA donor, activating its methyl group, which forms a C-C bond with C5 of the uridine moiety.