. "The mRNA-bound ribosomal complex moves along the 5'-untranslated region (5'-UTR) of the mRNA from its initial site to the initiation codon to form a 48S complex, in which the initiation codon (AUG) is base paired to the anticodon of the Met-tRNAi. It is not known whether eIF4A (or another ATPase, such as DED1) facilitates scanning by melting mRNA secondary structures or by actively propelling the ribosome."^^ . . . . . . . . . . . "Ribosomal scanning"^^ . . . . . .