This MedLibrary.org supplementary page on Leucine-zipper is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
 |
The introduction to this article provides insufficient context for those unfamiliar with the subject. Please help improve the article with a good introductory style. |
Proteins are made up of "strings" of amino acids. The specific amino acids and the order that they are found within a "string" constitute the primary structure of a specific protein. Once created, this primary structure or string of amino acids can be made into a secondary structure. Secondary structures include alpha helices and beta-sheets however "super" secondary structures can also be created, for example, leucine zippers.
A leucine zipper, aka leucine scissors1, is a super secondary structural motif found in proteins that creates adhesion forces in parallel alpha helices. It is a common dimerization domain found in some proteins involved in regulating gene expression.
Contents |
Structure
The main feature of the leucine zipper domain is the predominance of the common amino acid leucine at the d position of the heptad repeat. Leucine zippers were first identified by sequence alignment of certain transcription factors which identified a common pattern of leucines every seven amino acids. These leucines were later shown to form the hydrophobic core of a coiled 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 a DNA molecule through hydrogen bonding, and a hydrophobic leucine zipper region which is responsible for dimerization.
Biology
Leucine zipper regulatory proteins include c-fos and c-jun (the AP1 transcription factor), important regulators of normal development. If they are overproduced or mutated in a vital area, they may generate cancer. These proteins interact with the DNA as dimers (homo- or hetero-) and are also called basic zipper proteins (bZips).
References
- ^ David M. Glick, ed. (1997). "Leucine scissors". Glossary of Biochemistry and Molecular Biology (Revised ed.). London: Portland Press.
- 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. PubMed abstract
External links
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
This molecular biology article is a stub. You can help Wikipedia by expanding it. |
Wikipedia content modification information:
- This page was last modified on 2 January 2009, at 20:38.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Leucine-zipper".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.