Projects per year
PaaR2 is a putative transcription regulator encoded by a three-component parDE-like toxin-antitoxin module from Escherichia coli O157:H7. Although this module's toxin, antitoxin, and toxin-antitoxin complex have been more thoroughly investigated, little remains known about its transcription regulator PaaR2. Using a wide range of biophysical techniques (circular dichroism spectroscopy, size-exclusion chromatography-multiangle laser light scattering, dynamic light scattering, small-angle x-ray scattering, and native mass spectrometry), we demonstrate that PaaR2 mainly consists of α-helices and displays a concentration-dependent octameric build-up in solution and that this octamer contains a global shape that is significantly nonspherical. Thermal unfolding of PaaR2 is reversible and displays several transitions, suggesting a complex unfolding mechanism. The unfolding data obtained from spectroscopic and calorimetric methods were combined into a unifying thermodynamic model, which suggests a five-state unfolding trajectory. Furthermore, the model allows the calculation of a stability phase diagram, which shows that, under physiological conditions, PaaR2 mainly exists as a dimer that can swiftly oligomerize into an octamer depending on local protein concentrations. These findings, based on a thorough biophysical and thermodynamic analysis of PaaR2, may provide important insights into biological function such as DNA binding and transcriptional regulation.
Bibliographical noteCopyright © 2019 Biophysical Society. Published by Elsevier Inc. All rights reserved.
- Toxin-antitoxin module
- Transcription factors
- Molecular biophysics
- Protein chemistry
FWOAL831: Regulation of persistence by the paaAR-paaA2-parE2 and cog4197-duf1019 operons from E. coli O157
1/01/17 → 31/12/20
1/10/12 → 30/09/16
A unique hetero-hexadecameric architecture displayed by the E. coli O157 PaaA2-ParE2 antitoxin-toxin complexSterckx, Y. G., Jove, T., Shkumatau, A., Garcia Pino, A., Geerts, L., De Kerpel, M., Lah, J., De Greve, H., Van Melderen, L. & Loris, R., 2016, In : J Mol Biol. 428, p. 1589-1603 14 p.
Research output: Contribution to journal › Article15 Citations (Scopus)
New bactericidal toxins homologous to ParE belonging to 3-component toxin-antitoxin systems in Escherichia coli O157:H7.Hallez, R., Geeraerts, D., Sterckx, Y., Mine, N., Loris, R. & Van Melderen, L., 2010, In : Mol. Microbiol.. 76, p. 719-732 14 p.
Research output: Contribution to journal › Article