Your browser has javascript turned off or blocked. This will lead to some parts of our website to not work properly or at all. Turn on javascript for best performance.

The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Anders Irbäck. Photo.

Anders Irbäck

Professor

Anders Irbäck. Photo.

Stability and Local Unfolding of SOD1 in the Presence of Protein Crowders

Author

  • Anna Bille
  • Kristine Steen Jensen
  • Sandipan Mohanty
  • Mikael Akke
  • Anders Irbäck

Summary, in English

Using NMR and Monte Carlo (MC) methods, we investigate the stability and dynamics of superoxide dismutase 1 (SOD1) in homogeneous crowding environments, where either bovine pancreatic trypsin inhibitor (BPTI) or the B1 domain of streptococcal protein G (PGB1) serves as a crowding agent. By NMR, we show that both crowders, and especially BPTI, cause a drastic loss in the overall stability of SOD1 in its apo monomeric form. Additionally, we determine chemical shift perturbations indicating that SOD1 interacts with the crowder proteins in a residue-specific manner that further depends on the identity of the crowding protein. Furthermore, the specificity of SOD1-crowder interactions is reciprocal: chemical shift perturbations on BPTI and PGB1 identify regions that interact preferentially with SOD1. By MC simulations, we investigate the local unfolding of SOD1 in the absence and presence of the crowders. We find that the crowders primarily interact with the long flexible loops of the folded SOD1 monomer. The basic mechanisms by which the SOD1 β-barrel core unfolds remain unchanged when adding the crowders. In particular, both with and without the crowders, the second β-sheet of the barrel is more dynamic and unfolding-prone than the first. Notably, the MC simulations (exploring the early stages of SOD1 unfolding) and the NMR experiments (under equilibrium conditions) identify largely the same set of PGB1 and BPTI residues as prone to form SOD1 contacts. Thus, contacts stabilizing the unfolded state of SOD1 in many cases appear to form early in the unfolding reaction.

Department/s

  • Computational Biology and Biological Physics
  • Biophysical Chemistry
  • eSSENCE: The e-Science Collaboration

Publishing year

2019

Language

English

Pages

1920-1930

Publication/Series

Journal of Physical Chemistry B

Volume

123

Issue

9

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Other Physics Topics
  • Biophysics
  • Physical Chemistry

Status

Published

ISBN/ISSN/Other

  • ISSN: 1520-6106