What is a leucine zipper motif?
The leucine zipper (ZIP) motif consists of a periodic repetition of a leucine residue at every seventh position (heptad repeat) and forms an α-helical conformation, which facilitates dimerisation and in some cases higher oligomerisation of proteins by forming a parallel helix–helix association stabilised by formation …
Why does leucine zipper fold?
The leucine zipper is formed by amphipathic interaction between two ZIP domains. When these alpha helices dimerize, the zipper is formed. The hydrophobic side of the helix forms a dimer with itself or another similar helix, burying the non-polar amino acids away from the solvent.
What is a leucine zipper transcription factor?
The basic leucine zipper (bZIP) transcription factors are sequence-specific DNA-binding proteins that regulate transcription. They are characterized by a 60-80 amino acid bZIP domain: a basic DNA binding domain followed by a leucine zipper dimerization domain.
How is leucine zipper held together?
A leucine zipper is formed by two α helices, one from each monomer. The helices are held together by hydrophobic interactions between leucine residues, which are located on one side of each helix.
Is leucine a hydrophobic?
Leucine, an essential amino acid, is one of the three amino acid with a branched hydrocarbon side chain. Like valine, leucine is hydrophobic and generally buried in folded proteins.
Are leucine zippers transcription factors?
Basic-region leucine zipper (bZIP) proteins are one of the largest transcription factor families that regulate a wide range of cellular functions. Owing to the stability of their coiled coil structure leucine zipper (LZ) domains of bZIP factors are widely employed as dimerization motifs in protein engineering studies.
Is leucine zipper a coiled coil?
X-ray crystal studies have demonstrated that the leucine zipper is a dimeric parallel coiled coil (7, 8) that structurally repeats itself every two α-helical turns or every heptad (seven amino acids). Amino acid positions in each heptad are identified using the nomenclature (a,b,c,d,e,f,g)n (9).
Is leucine zipper a domain?
Leucine zipper domains are made up of two motifs: a basic region that recognizes a specific DNA sequence and a series of leucines spaced 7 residues apart along an α-helix (leucine zipper) that mediate dimerization.
What is the function of a Leucine Zipper?
The Leucine Zipper and the Basic DNA-Binding Domain (bZIP) This leucine zipper facilitates the dimerization of the protein by interdigitation of two leucine containing helices on different molecules and these residues form the buried subunit interface of the coiled-coil dimer.
Is too much leucine bad for you?
Very high doses of leucine may cause low blood sugar (hypoglycemia). It may also cause pellagra. Symptoms of this can include skin lesions, hair loss, and gastrointestinal problems.
How is the leucine zipper motif related to DNA binding?
The Leucine Zipper Motif Mediates Both DNA Binding and Protein Dimerization. Usually, the portion of the protein responsible for dimerization is distinct from the portion that is responsible for DNA binding (see Figure 7-14 ). One motif, however, combines these two functions in an elegant and economical way.
Where is the ZIP domain of the leucine zipper located?
The leucine zipper is formed by amphipathic interaction between two ZIP domains. The ZIP domain is found in the alpha-helix of each monomer, and contains leucines, or leucine-like amino acids.
How are dimers of leucine zipper proteins dimerize?
These motifs form a continuous α-helix that can dimerize through formation of a coiled-coil structure involving paired contacts between hydrophobic leucine zipper domains (Fig. 10.14D; also see Fig. 3.10 ). Dimers of leucine zipper proteins recognize short, inverted, repeat sequences.
Where are leucine like amino acids found in DNA?
These basic residues interact in the major groove of the DNA, forming sequence-specific interactions. The leucine zipper is formed by amphipathic interaction between two ZIP domains. The ZIP domain is found in the alpha-helix of each monomer, and contains leucines, or leucine-like amino acids.