C-JUN
From Proteopedia
Andrew Rebeyka
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Introduction
The c-Jun protein is a member of transcription factors which consist of a basic region leucine zipper region [1]. All these leucine zipper factors bind to DNA in one of two states: homo or heterodimers [1].. In conjunction with the c-Fos protein these two proteins bind to specific regions of DNA strands. Together these two proteins form the c-fos/c-jun complex which help regulate cell growth and differentiation [1]. Regulation of the complex iteslf is done by interactions between the protein and DNA in addition to the protein-protein interactions between each of the leucine zipper domains [1].
Structure Overview
The structure of c-Jun is comprised of a leucine zipper as previously stated. This dimerization motif may be in one of two classes, both of which are required for DNA-binding transcription factors; the basic-domain leucine zipper proteins (bZIP) and the basic helix loop-helix-leucine zipper proteins(bHLH-ZIP) [3]. As can be been in the figure XXXXX, the strand becomes an elongated coiled coil. This is formed by residues at the a and d positions in each of the two monomers, whereby they create hydrophobic centers which conform to the "knobs into holes" model by Crick. [3]. amino acids at these a and d positions are each surrounded by 4 additional residues from adjacent a-helix monomer [3].
the a and d residues each exhibit varying types of packing in terms of this "knobs into holes" theory. According to Harbury et al.(24) the leucines at the a positions are packed "parallel" in such a way that the C-alpha-C-beta bond vector lies in a parallel manner to the C-alpha-C-alpha vector at the base of the acceptor hole on adjacent helix [1]. Whereas the opposite is true for the leucines in the d positions. Here the residues are packed in a "perpendicular" nature [1]. The bond vector of the C-alpha-C-beta pack approximately perpendicular to the C-alpha-C-alpha vector at the base of the hole of the second helix in which it packs [1]. therefore only the leucine side chains in the a positions, which point away from the boundary, make van der Waals interactions [1].
This protein is a dimer that is completely symmetrical [3].
It is comprised of a coiled coil of two alpha helices [3]Proteopedia Page Contributors and Editors (what is this?)
Andrew Rebeyka, Michal Harel, Alexander Berchansky, David Canner, Andrea Gorrell
