C-terminal W2 domain of eukaryotic translation initiation factor 2B epsilon
eIF2B is a heteropentameric complex which functions as a guanine nucleotide exchange factor in the recycling of eIF-2 during the initiation of translation in eukaryotes. The epsilon and gamma subunits are sequence similar and both are essential in yeast. Epsilon appears to be the catalytically active subunit, with gamma enhancing its activity. The C-terminal domain of the eIF2B epsilon subunit contains bipartite motifs rich in acidic and aromatic residues, which are responsible for the interaction with eIF2. The structure of the domain resembles that of a set of concatenated HEAT repeats.