The leucine zipper domain of the Max gene product is not an autonomous dimerization site
✍ Scribed by Carlos García-Echeverría
- Book ID
- 104632398
- Publisher
- Springer Netherlands
- Year
- 1995
- Tongue
- English
- Weight
- 529 KB
- Volume
- 1
- Category
- Article
- ISSN
- 1573-3149
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✦ Synopsis
Transcriptional factors are proteins that bind to specific regulatory DNA sequences controlling the synthesis of RNA from DNA templates. Among such factors, increasing attention has been devoted to the Max gene product, the specific partner for the c-Myc oncoprotein. Productive DNA binding by Max requires dimerization, which is mediated by specific interactions of its helix-loop-helix leucine zipper binding domain. The Max-DNA complex crystallizes as a parallel, left-handed, four-helix bundle structure with the leucine zipper region forming a parallel coiled-coil. In this paper, it is shown by circular dichroism spectroscopy that the leucine zipper domain of the transcriptional factor described above (Max 75-103) is not an autonomous folding unit. The lack of dimerization function has been ascribed to the probably destabilizing effect of histidine and asparagine residues at the dimerization interface. The hydrophobic mutation of one of these amino acids (Asn 92 ~ Val) results in the formation of a coiled-coil structure.