Contacts between mammalian mitochondrial translational initiation factor 3 and ribosomal proteins in the small subunit

► Mitochondria synthesize 13 proteins using a specialized protein biosynthetic system. ► Mitochondrial ribosomes have many proteins with no homologs in other systems. ► Ribosomal proteins at the binding site of initiation factor 3 were identified. ► IF3mt has very different contacts with the ribosome than observed with bacterial IF3.