Structural and DNA-binding properties of the cytoplasmic domain of Vibrio cholerae transcription factor ToxR
| Autor: | Christoph Göbl, Walter Becker, Klaus Zangger, Nina Gubensäk, Evelyne Schrank, Sergio Pulido, Tobias Madl, N. Helge Meyer, Christoph Hartlmüller, Fabio S. Falsone, Joachim Reidl, Gabriel E. Wagner, Tea Pavkov-Keller |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Transcription
Genetic nuclear magnetic resonance (NMR) TCP toxin coregulated pilus medicine.disease_cause Biochemistry chemistry.chemical_compound Bacterial Proteins Protein Domains Transcription (biology) medicine membrane protein protein interaction Molecular Biology Gene Transcription factor Vibrio cholerae transcription factor Helix-Turn-Helix Motifs Activator (genetics) CT cholera toxin Cell Biology DNA-binding domain wHTH winged helix–turn–helix CSP chemical shift perturbation Cell biology ddc DNA-Binding Proteins chemistry Membrane protein DNA Research Article Transcription Factors |
| Zdroj: | The Journal of Biological Chemistry |
| Popis: | ToxR represents an essential transcription factor of Vibrio cholerae, which is involved in the regulation of multiple, mainly virulence associated genes. Its versatile functionality as activator, respressor or co-activator suggests a complex regulatory mechanism, whose clarification is essential for a better understanding of the virulence expression system of V. cholerae. Here, we provide structural information elucidating the organization and binding behaviour of the cytoplasmic DNA binding domain of ToxR (cToxR), containing a winged helix-turn-helix (wHTH) motif. Our analysis reveals unexpected structural features of this domain expanding our knowledge of a poorly-defined subfamily of wHTH proteins. cToxR forms an extraordinary long α-loop and furthermore has an additional C-terminal beta strand, contacting the N-terminus and thus leading to a compact fold. The identification of the exact interactions between ToxR and DNA contributes to a deeper understanding of this regulatory process. Our findings not only show general binding of the soluble cytoplasmic domain of ToxR to DNA, but also indicate a higher affinity for the toxT motif. These results support the current theory of ToxR being a 'DNA-catcher' to enable binding of the transcription factor TcpP and thus activation of virulence-associated toxT transcription. Although, TcpP and ToxR interaction is assumed to be crucial in the activation of the toxT genes, we could not detect an interaction event of their isolated cytoplasmic domains. We therefore conclude that other factors are needed to establish this protein-protein interaction, e.g., membrane attachment, the presence of their full-length proteins and/or other intermediary proteins that may facilitate binding. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|