In leucine zipper model, Leucine residue is seen after every

*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. * 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 <img class="fr-dib" style="width: 300px;" src=" /> Ref : Biochemistry by U. Satyanarayana 3rd edition Pgno : 574