A mammalian mitochondrial serine transfer RNA lacking the "dihydrouridine" loop and stem

A unique transfer RNA has been identified in human and bovine mitochondria that lacks the "dihydrouridine" loop and stem structure. This tRNA is mitochondrially coded as shown by DNA sequence analysis of the human and bovine mitochondrial DNA. Sequence analysis of the RNA shows that it is post-transcriptionally modified by the addition of CCA at the 3' terminus and that at least one base is modified. As predicted by its anticodon (GCU, corresponding to the serine codons AGU/C) this tRNA can be aminoacylated with serine when purified mitochondria are incubated in a medium containing 3H-serine.