Structural preferences and stabilisation of molecular assemblies with sugars, peptide models and water molecules probed in the gas phase
supervised by Pierre Çarçabal
The understanding of isolated molecular assemblies between sugars and peptide models is of great importance in the biological context of molecular recognition. The influence of water in the formation of these structures is also not to be neglected. The stable structures of these systems, as well as the various non-covalent interactions stabilising them are studied in the gas phase with laser spectroscopy coupled to mass-spectrometry detection. This experimental part is sustained by a theoretical study that consists in exploring the conformational landscape and calculating the vibrational frequencies with methods of quantum chemistry. In this thesis, the structures formed through the interaction of mannose with different
peptide models are studied while slightly changing the local environment of mannose. A very flexible photosensitiser model is first studied. The interactions of sugars with peptide models in neutral and charged environments are also probed. Several structures with high relative energy are observed, revealing a secondary pathway of quick kinetic cooling during the formation of the assemblies. The importance of the environment – water, or charge – is also shown. Finally, the experimental development of a new evaporation source of molecules and clusters in vacuo from a liquid microjet is discussed.