Health / Medical Topics |
Leucine Zipper
Definition 1
Domains in DNA-binding proteins that contain amino acid sequences that show periodic arrays of leucine residues. These residues exist in an alpha-helical conformation, with the leucine side chains extending from one alpha helix interdigitating with those displayed from a similar alpha helix of a second polypeptide, facilitating dimerization. (NCI Thesaurus)
Definition 2
DNA-binding motifs formed from two alpha-helixes which intertwine for about eight turns into a coiled coil and then bifurcate to form Y shaped structures. Leucines occurring in heptad repeats end up on the same sides of the helixes and are adjacent to each other in the stem of the Y (the "zipper" region). The DNA-binding residues are located in the bifurcated region of the Y. (NLM, Medical Subject Headings)