Several structural features make the initiator tRNA unique. For example, it has specific nucleotide sequences in its anticodon loop and acceptor stem that are recognized by initiation factors. Additionally, the initiator tRNA is charged with methionine, which is often formylated in prokaryotes to form N-formylmethionine (fMet). This formylation helps the initiator tRNA distinguish itself from other tRNAs and ensures the fidelity of translation initiation.
