<prompt> In leucine zipper model, Leucine residue seen after every3 amino acids6 amino acids7 amino acids12 amino acids  <response>: An a helix in which there is a periodic repeat of leucine residues at every seventh position. This occurs for eight helical turns and four leucine repeats. Similar structures have been found in a number of other proteins associated with the regulation of transcription in mammalian and yeast cells. shown in the table below It is thought that this structure allows two identical monomers or heterodimers eg, Fos-Jun or Jun-Jun to zip together in a coiled-coil and form a tight dimeric complex This protein-protein interaction may serve to enhance the association of the separate DNA binding domains with their target 