The eIF5-mimic protein 1/2 (also known as basic leucine zipper and W2 domain-containing proteins 2 and 1 (BZW2 and BZW1), respectively), are paralogous human proteins containing C-terminal HEAT domains that resemble the HEAT domain of eIF5 []. BZW1 plays an important role in the cell cycle and transcriptionally control the histone H4 gene during G1/S phase []. The Drosophila ortholog, kra (krasavietz) or exba (extra bases), may be involved in translational inhibition in neural development. The structure of this C-terminal W2 domain resembles that of a set of concatenated HEAT repeats [, , ].The W2 domain has a globular fold and is exclusively composed out of α-helices [, , ]. The structure can be divided into a structural C-terminalcore onto which the two N-terminal helices are attached. The core contains two aromatic/acidic residue-rich regions (AA boxes), which are important for mediating protein-protein interactions.
