Sequence-specific destabilization of azurin by tetramethylguanidinium-dipeptide ionic liquids

Roshani Patel, Austin K. Clark, Gabriella DeStefano, Isabella DeStefano, Hunter Gogoj, Erin Gray, Aashka Y. Patel, Joshua T. Hauner, Gregory A. Caputo, Timothy Vaden

Research output: Contribution to journalArticlepeer-review


The thermal unfolding of the copper redox protein azurin was studied in the presence of four different dipeptide-based ionic liquids (ILs) utilizing tetramethylguanidinium as the cation. The four dipeptides have different sequences including the amino acids Ser and Asp: TMG-AspAsp, TMG-SerSer, TMG-SerAsp, and TMG-AspSer. Thermal unfolding curves generated from temperature-dependent fluorescence spectroscopy experiments showed that TMG-AspAsp and TMG-SerSer have minor destabilizing effects on the protein while TMG-AspSer and TMG-SerAsp strongly destabilize azurin. Red-shifted fluorescence signatures in the 25 °C correlate with the observed protein destabilization in the solutions with TMG-AspSer and TMG-SerAsp. These signals could correspond to interactions between the Asp residue in the dipeptide and the azurin Trp residue in the unfolded state. These results, supported by appropriate control experiments, suggest that dipeptide sequence-specific interactions lead to selective protein destabilization and motivate further studies of TMG-dipeptide ILs.

Original languageEnglish (US)
Article number101242
JournalBiochemistry and Biophysics Reports
StatePublished - Jul 2022

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry


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