Sometimes called bZIP motifs. A dimer of two long alpha helices which look like forceps pinching a piece of DNA. These helices contain a large number of the amino acid leucine, which forms an interdigitating hydrophobic interface allowing the helices to stick. The leucines occur at regular intervals in the sequence, seven residues apart. In many cases, the joining of the two components of the zipper are linked to DNA binding (cooperativity), allowing these proteins to regulate DNA transcription, such as the Fos and Jun proteins. These have a high degree of homology to GCN4 which is a yeast leucine zipper that also binds DNA.

schematic of a leucine zipper

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