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TY - JOUR AU - Weiss, Michael A. AU - Ellenberger, Thomas AU - Wobbe, C. Richard AU - Lee, Jonathan P. AU - Harrison, Stephen C. AU - Struhl, Kevin PY - 1990 DA - 1990/10/01 TI - Folding transition in the DMA-binding domain of GCN4 on specific binding to DNA JO - Nature SP - 575 EP - 578 VL - 347 IS - 6293 AB - PROTEIN-DNA recognition is often mediated by a small domain containing a recognizable structural motif, such as the helix–turn–helix1 or the zinc-finger2. 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 binding3. Here we describe circular dichroism and 1NMR spectroscopic studies of another family member, the yeast transcriptional activator GCN44,5. The 58-residue DNA-binding domain of GCN4, GCN4-p, exhibits a concentration-dependent α-helical transition, in accord with previous studies of the dimerization properties of an isolated leucine-zipper peptide6. The GCN4-p dimer is ∼70% helical at 25 °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 α-helix content of GNC4-p to at least 95%. Thus, the basic region acquires substantial α-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 α-helix content. Our results indicate that the GCN4 basic region is significantly unfolded at 25 °C and that its folded, α-helical conformation is stabilized by binding to DNA. SN - 1476-4687 UR - https://doi.org/10.1038/347575a0 DO - 10.1038/347575a0 ID - Weiss1990 ER -