Folding transition in the DMA-binding domain of GCN4 on specific binding to DNA
| Autor: | Kevin Struhl, Stephen C. Harrison, C R Wobbe, Michael A. Weiss, Jeng-Shin Lee, Thomas E. Ellenberger |
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| Rok vydání: | 1990 |
| Předmět: |
Leucine zipper
Magnetic Resonance Spectroscopy Saccharomyces cerevisiae Proteins Macromolecular Substances Protein Conformation Proto-Oncogene Proteins c-jun Base pair Molecular Sequence Data Biology Fungal Proteins chemistry.chemical_compound Protein structure Amino Acid Sequence Binding site Cyclic AMP Response Element-Binding Protein Structural motif Leucine Zippers Binding Sites Multidisciplinary Base Sequence Circular Dichroism Blood Proteins DNA DNA-binding domain Activating Transcription Factors DNA-Binding Proteins Biochemistry chemistry Biophysics Protein Kinases Transcription Factors Binding domain |
| Zdroj: | Nature. 347:575-578 |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/347575a0 |
| Popis: | Protein-DNA recognition is often mediated by a small domain containing a recognizable structural motif, such as the helix-turn-helix or the zinc-finger. These motifs are compact structures that dock against the DNA double helix. Another DNA recognition motif, found in a highly conserved family of eukaryotic transcription factors including C/EPB, Fos, Jun and CREB, consists of a coiled-coil dimerization element the leucine-zipper and an adjoining basic region which mediates DNA binding. Here we describe circular dichroism and 1H-NMR spectroscopic studies of another family member, the yeast transcriptional activator GCN4. The 58-residue DNA-binding domain of GCN4, GCN4-p, exhibits a concentration-dependent alpha-helical transition, in accord with previous studies of the dimerization properties of an isolated leucine-zipper peptide. The GCN4-p dimer is approximately 70% helical at 25 degrees C, implying that the basic region adjacent to the leucine zipper is largely unstructured in the absence of DNA. Strikingly, addition of DNA containing a GCN4 binding site (AP-1 site) increases the alpha-helix content of GNC4-p to at least 95%. Thus, the basic region acquires substantial alpha-helical structure when it binds to DNA. A similar folding transition is observed on GCN4-p binding to the related ATF/CREB site, which contains an additional central base pair. The accommodation of DNA target sites of different lengths clearly requires some flexibility in the GCN4 binding domain, despite its high alpha-helix content. Our results indicate that the GCN4 basic region is significantly unfolded at 25 degrees C and that its folded, alpha-helical conformation is stabilized by binding to DNA. |
| Databáze: | OpenAIRE |
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