Formyl-met-tRNA is formed by addition of methionine to tRNA fMet (formyl-methionine specific-tRNA) by the fMet-tRNA synthetase to produce methioninetRNA and then transfer of formyl group from N10 formyltetrahydrofolate to the amino group of the Met residue to produce N-formyl methionine tRNA. Binding of 30 S ribosomal subunit to two initiation factors, IF-1 and IF-3 initiates translation. Factor IF-3 prevents the 30 s and 50 S subunits from combining prematurely and mediated binding of mRNA to 30 S subunit. This is followed by binding of complex consisting of the 30 s ribosomal subunit, IF-3, and mRNA with the initiating formyl met tRNA in presence of GTP-bound IF-2. The pairing of anticodon of tRNA with the mRNAs initiation codon induces binding of 50 S ribosomal subunit. Thus, association of 30 S mRNA with formylmet-tRNA required GTP.