43S complex ternary complex 40S:eIF3:eIF1A Formation of the 43S pre-initiation complex Pubmed429297 Pubmed592399 Pubmed641056 Reactome Database ID Release 4372691 Reactome, http://www.reactome.org ReactomeREACT_1354 The ternary complex (Met-tRNAi:eIF2:GTP) binds to the complex formed by the 40S subunit, eIF3 and eIF1A, to form the 43S complex. eIF1A promotes binding of the ternary complex to the 40S subunit within 43S. The initiator methionyl-tRNA from the ternary complex is positioned at the ribosomal P site.