The eEF1B complex binds to eEF1A and regulates its activity by catalyzing the release of GDP. Subsequently, GTP is able to bind eEF1A allowing the formation of the ternary complex (eEF1A-GTP-aa-tRNA).In metazoans eEF1 protein family is composed of four subunits: eEF1A and eEF1B alpha, beta, and gamma (formerly EF-1alpha, EF-1beta, EF-1delta, and EF-1gamma, respectively). Both eEF1B alpha and eEF1B beta function as nucleotide exchange proteins. eEF1B gamma associates with eEF1B alpha and stimulates its exchange activity.
This process is illustrated below with a GTP molecule in white and eEF1A protein in yellow.The three subunits of eEF1B are also shown.