In situ investigation of the interaction between water and small peptides on Au(110) and Cu(110) surfaces using near ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) and reflection anisotropy spectroscopy (RAS)

• Applicants: Professor Dr. Norbert Esser; Dr. Roland Hergenröder
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Analytical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 268794613

The goal of this project is to gain insight into the processes involved in interactions between water and biomolecules at metal surfaces. In particular, we want to elucidate the following questions regarding small biomolecules on metal surfaces: How do they adsorb to the surface? How do they interact at the surface? What is the role of water in these processes? And what is the influence of co-adsorbed metal ions? Therefore, we plan to study the interactions of water and small peptides on metal surfaces by investigating the effects of the surface structure and the environment (pressure, temperature, and pH) on these processes. This will include a study of the influence of water on the decomposition reactions of amino acids on metal surfaces. These phenomena will be studied with near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS), a new technique that allows us to study the surface structure at the molecular level in situ under more realistic pressure and temperature conditions. This study will be complemented by reflection anisotropy spectroscopy (RAS) measurements, providing information about bonding and orientation of adsorbed molecules on the surface. Other experimental methods will be used for further characterisation of the surfaces. These include LEED, STM, ellipsometry, and ir, and Raman spectroscopy. We will use single crystal surfaces of two metals: gold and copper as models for an inert and a reactive surface, respectively. The system of glutathione (g-Glu-Cys-Gly, GSH), its component amino acids, and the structurally related di-peptides g-glutamylcysteine (g-Glu-Cys) and L-cysteinylglycine (Cys-Gly) will be the main focus of our study. L-cysteine will be our control molecule, as the interaction of this species with both metal surfaces has been studied extensively.

• DFG Programme: Research Grants
• International Connection: Austria
• Cooperation Partners: Privatdozent Dr. Karsten Hinrichs; Professor Dr. Wolf Gero Schmidt; Professor Dr. Peter Zeppenfeld