28S subunit:MTIF3 binds MTIF2:GTP, mRNA, and formylMet-tRNA

As inferred from bovine homologs, the 28S ribosomal subunit in a complex with MTIF3 (IF-3Mt, IF3mt) binds mRNA and, at some point, MTIF2:GTP (IF-2Mt:GTP, IF2mt:GTP). If an initiation codon is present at the 5' end of the mRNA then MTIF2:GTP assists the binding of N-formylmethionyl-tRNA and a stable, productive initiation complex results. If no initiation codon is present, the mRNA slides through the 28S subunit and then dissociates.

据此推断，从牛的同源物中得知，28S核糖体亚基与MTIF3（IF-3Mt，IF3mt）形成的复合物结合mRNA，并在某一时刻与MTIF2：GTP（IF-2Mt：GTP，IF2mt：GTP）结合。若mRNA的5'端存在起始密码子，则MTIF2：GTP将协助N-甲酰甲硫氨酰-tRNA的结合，从而形成稳定且高效的起始复合物。若不存在起始密码子，则mRNA将滑过28S亚基并随后解离。