Impact of ionic liquids on the conformation of peptides and proteins

• Applicant: Professor Dr. Frank Bordusa
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2008 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 91789813

In order to elucidate ionic liquid/peptide structure relationships and specific interactions we were able to successfully establish high-resolution magic angle spinning (HR-MAS) NMR spectroscopy as central tool during the first funding period. From the results we can conclude that proton NMR chemical shift changes of peptide signals upon dissolving in ionic liquids arise from a unique direct interaction between the ILs and peptides and from an IL-induced conformational change in certain peptide regions. The application of the powerful and efficient HR-MAS approach to studies of elongated structured peptides and proteins dissolved preferentially in imidazolium-based ILs represents the focus of the renewal proposal. Potential factors having an influence on the strength, position and type of interactions between ILs and peptides will be investigated in more detail. For this purpose, various experimental approaches are planned, such as the use of a series of ILs with different cation and anion structures to clarify the role of these ions for hydrogen bond effects with corresponding peptide sites, temperature-dependent measurements of IL/peptide systems to monitor conformational changes of the peptides, concentration-dependent studies to get information on the stoichiometry of IL/peptide interactions, 13C and 15N HR-MAS NMR investigations of the deuterium isotope effect of deuterated IL/peptide systems to elucidate hydrogen bonding behaviour and the evaluation of aH peptide chemical shifts to get information on secondary structure formation. Detailed insights into the interaction of ionic liquids with peptidic structures will help to clarify the reasons for conformational stabilization and destabilization effects of peptides upon dissolving in ionic liquids.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1191: Ionic Liquids
• Participating Person: Dr. Carmen Mrestani-Klaus (†)