- Leucine zipper
[
helical wheel diagram, of a leucine zipper, where d represent amino acid leucine , arranged with otheramino acids on two parallelalpha helices .]A leucine zipper, aka leucine scissors [cite encyclopedia | editor = David M. Glick| encyclopedia = Glossary of Biochemistry and Molecular Biology | title = Leucine scissors | edition = Revised | year = 1997 | publisher = Portland Press | volume = | location = London | quote = ] , is a super secondary
structural motif found inproteins that creates adhesion forces in parallelalpha helices . It is a common dimerization domain found in some proteins involved in regulatinggene expression .tructure
The main feature of the leucine zipper domain is the predominance of the common
amino acid leucine at the "d" position of theheptad repeat . Leucine zippers were first identified bysequence alignment of certain transcription factors which identified a common pattern of leucines every seven amino acids. These leucines were later shown to form thehydrophobic core of acoiled coil .Each half of a leucine zipper consists of a short
alpha-helix with a leucine residue at every seventh position. The standard 3.6 residues per turn alpha-helix structure changes slightly to become a 3.5 residues per turn alpha-helix. Known also as the heptat repeat, one leucine comes in direct contact with another leucine on the other strand every second turn.The bZip family of transcription factors consist of a basic region which interacts with the
major groove of aDNA molecule throughhydrogen bonding , and ahydrophobic leucine zipper region which is responsible for dimerization.Biology
Leucine zipper regulatory proteins include
c-fos andc-jun (the AP1 transcription factor), important regulators of normal development. If they are overproduced or mutated in a vital area, they may generatecancer . These proteins interact with the DNA as dimers (homo- or hetero-) and are also called basic zipper proteins (bZips).References
* Landschulz WH, Johnson PF, McKnight SL. (1988) The leucine zipper: a hypothetical structure common to a new class of DNA-binding proteins. "Science" 240:1759-1764. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3289117&query_hl=5 PubMed abstract]External links
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