Preferential heterodimer formation by isolated leucine zippers from fos and jun.
The products of the nuclear oncogenes fos and jun are known to form heterodimers that bind to DNA and modulate transcription. Both proteins contain a leucine zipper that is important for heterodimer formation. Peptides corresponding to these leucine zippers were synthesized. When mixed, these peptides preferentially form heterodimers over homodimers by at least 1000-fold. Both homodimers and the heterodimer are parallel alpha helices. The leucine zipper regions from Fos and Jun therefore correspond to autonomous helical dimerization sites that are likely to be short coiled coils, and these regions are sufficient to determine the specificity of interaction between Fos and Jun. The Fos leucine zipper forms a relatively unstable homodimer. Instability of homodimers provides a thermodynamic driving force for preferential heterodimer formation.
O'Shea
E K
EK
Whitehead Institute for Biomedical Research, Cambridge, MA 02142.
Rutkowski
R
R
Stafford
W F
WF
Kim
P S
PS
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D004268:DNA-Binding Proteins; D004220:Disulfides; D007930:Leucine; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D004220:Disulfides; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D007930:Leucine