Understanding the effect of solvation on the structure of ion-peptide complexes, one water molecule at a time

• Applicant: Dr. Katharina Meyer
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452620003

The goal of the project „Understanding the effect of solvation on the structure of ion-peptide complexes, one water molecule at a time“ is to study the impact of solvation on the structure of metal ion-peptide complexes in solution, in order to examine the interplay of various non-covalent interactions on the structure, namely ion-solute, ion-solvent, solute-solvent, and intramolecular hydrogen bonding of the peptide itself.Peptides are important model systems for larger biomolecules such as proteins or enzymes, whose function is affected by metal ions in solution. An example is the Hofmeister effect, which ranks the impact of ion size and charge on the solubility of proteins in aqueous solution. This and other specific ion effects are still not completely understood on a microscopic level, but ion-solute and ion-solvent interactions are thought to be decisive. Within the course of this project, these effects will be systematically studied by variation of the metal ion size and interaction strength, peptide chain length, and the number of water molecules. For that, the complexes will be prepared in the gas phase, mass selected, and interrogated with vibrational spectroscopy. The advantage of this approach is that a distinct complex can be formed and examined in great detail, whereas the multitude of different structures present in the condensed phase limits any information about the contribution of individual effects. The variety of different structures and the subtle interplay of various non-covalent interactions studied further enables a critical evaluation of the performance of quantum chemical calculations in form of a benchmark, which is important for the development of new and cost-efficient methodologies.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Etienne Garand