ID   2.3.1.311
DE   tRNA carboxymethyluridine synthase.
CA   acetyl-CoA + H2O + S-adenosyl-L-methionine + uridine(34) in tRNA =
CA   5'-deoxyadenosine + 5-(carboxymethyl)uridine(34) in tRNA + CoA + 2 H(+) +
CA   L-methionine.
CC   -!- The enzyme, found in eukaryotes, most archaea, and some bacteria,
CC       catalyzes the first step in modification of the wobble uridine base
CC       of certain tRNAs.
CC   -!- In eukaryotes the enzyme is a complex of six conserved subunits, with
CC       ELP3 being the catalytic subunit.
CC   -!- In archaea and bacteria the enzyme consists of a single subunit,
CC       homologous to ELP3.
CC   -!- The enzyme contains an [4Fe-4S] cluster and uses radical chemistry. A
CC       5'-deoxyadenosyl radical generated in the radical AdoMet (SAM) domain
CC       attacks the acetyl-CoA donor, activating its methyl group, which
CC       forms a C-C bond with C5 of the uridine moiety.
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