Leucine zipper

You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.

Jump to: navigation, search
Please help improve this article by expanding it.
Further information might be found on the talk page or at requests for expansion.
This article has been tagged since November 2007.
The introduction to this article provides insufficient context for those unfamiliar with the subject.
Please help improve the article with a good introductory style.
It has been suggested that this article or section be merged with bZIP domain. (Discuss)
Image:Coiledcoil-wheelcartoon.gif
"Overhead view", or helical wheel diagram, of a leucine zipper, where d represent amino acid leucine , arranged with other amino acids on two parallel alpha helices.

A leucine zipper, aka leucine scissors[1], 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

Image:Leucine zipper.png
Leucine Zipper (blue) bound to DNA. The leucine residues that represent the 'teeth' of the zipper are colored red

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 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

  • 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

v • d • e
Transcription factors and intracellular receptors
(1) Basic domains
(1.1) Basic leucine zipper (bZIP) Activating transcription factor (1, 2, 3, 4, 5, 6) • AP-1 (c-Fos, FOSB, FOSL1, FOSL2, c-Jun, JUNB, JUND) • BACH (1, 2) • C/EBP (α, β, γ, δ, ε, ζ) • CREB (1, 3) • GABPA • MAF (B, F, G, K) • NRL • NRF1 • XBP1
(1.2) Basic helix-loop-helix (bHLH) ATOH1 • AhR • AHRR • ARNT • ASCL1 • BMAL (ARNTL, ARNTL2) • CLOCK • HIF (1A, 3A) • Myogenic regulatory factors (MyoD, Myogenin, MYF5, MYF6) • NEUROD1 • Twist • USF1
(1.3) bHLH-ZIP Myc • MITF • SREBP (1, 2)
(1.6) Basic helix-span-helix (bHSH) AP-2
(2) Zinc finger
DNA-binding domains
(2.1) Nuclear receptor (Cys4) subfamily 1 (Thyroid hormone (α, β), CAR, FXR, LXR (α, β), PPAR (α, β/δ, γ), PXR, RAR (α, β, γ), ROR (α, β, γ), Rev-ErbA (α, β), VDR) • subfamily 2 (COUP-TF (I, II), Ear-2, HNF4 (α, γ), PNR, RXR (α, β, γ), Testicular receptor (2, 4), TLX) • subfamily 3 (Steroid hormone (Estrogen (α, β), Estrogen related (α, β, γ), Androgen, Glucocorticoid, Mineralocorticoid, Progesterone)) • subfamily 4 NUR (NGFIB, NOR1, NURR1) • subfamily 5 (LRH-1, SF1) • subfamily 6 (GCNF) • subfamily 0 (DAX1, SHP)
(2.2) Other Cys4 GATA (1, 2, 3, 4, 5, 6)
(2.3) Cys2His2 General transcription factors (TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH: 1, 2) • GLI-Krüppel family (1, 2, 3, YY1) • KLF (2, 4, 5, 6, 10, 11, 12, 13) • Sp1 • zinc finger (3, 35, 43, 146, 148, 165, 217, 268, 281, 350) • Zbtb7 (7A) • ZBT (16, 17, 33)
(2.4) Cys6 HIVEP1
(3) Helix-turn-helix
domains
(3.1) Homeo domain ARX • Homeobox (A1, A3, A4, A5, A7, A9, A10, A11, A13, B1, B2, B3, B4, B5, B6, B7, B8, B9, B13, C4, C6, C8, C9, C13, D1, D3, D4, D9, D10, D11, D12, D13) • NANOG • NKX (2-1, 2-5, 3-1) • POU domain (PIT-1, BRN-3: 1, 2, Octamer transcription factor: 1, 2, 3/4, 6, 7)
(3.2) Paired box PAX (1, 2, 3, 4, 5, 6, 7, 8, 9)
(3.3) Fork head / winged helix E2F (1, 2, 3, 4, 5) • FOX proteins (C1, C2, E1, G1, H1, L2, M1, N3, O3, O4, P1, P2, P3)
(3.4) Heat Shock Factors HSF1
(3.5) Tryptophan clusters ELF (4, 5) • Interferon regulatory factors (1, 2, 3, 4, 5, 6, 7, 8) • MYB
(3.6) TEA domain transcriptional enhancer factor 1, 2
(4) β-Scaffold factors with
minor groove contacts
(4.1) Rel homology region NF-κB (NFKB1, NFKB2, REL, RELA, RELB) • NFAT (5, C1, C2, C3, C4)
(4.2) STAT STAT (1, 2, 3, 4, 5, 6)
(4.3) p53 p53
(4.4) MADS box Mef2 (A, B, C, D) • SRF
(4.7) High mobility group HNF (1A, 1B) • LEF1 • SOX (3, 4, 6, 9, 10, 13, 18) • SRY • SSRP1
(4.10) Cold-shock domain CSDA
(0) Other
transcription factors
(0.2) HMGI(Y) HMGA (1, 2)
(0.3) Pocket domain Rb • RBL1 • RBL2
(0.6) Miscellaneous ARID (1A, 1B, 2, 3A, 3B, 4A) • CAP • Rho/Sigma • R-SMAD

de:Leucin-Zipper

Retrieved from "http://en.wikidoc.org/index.php/Leucine_zipper"
Personal tools