De Bruyn, P, Hadži, S, Vandervelde, A et al. (7 more authors) (2019) Thermodynamic Stability of the Transcription Regulator PaaR2 from Escherichia coli O157:H7. Biophysical Journal, 116 (8). pp. 1420-1431. ISSN 0006-3495
Abstract
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.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Biophysical Society. This is an author produced version of a paper published in Biophysical Journal. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Jun 2019 11:06 |
Last Modified: | 28 Mar 2020 01:38 |
Status: | Published |
Publisher: | Cell Press |
Identification Number: | 10.1016/j.bpj.2019.03.015 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:146905 |