8th February 2007 – 15:00
Prof. Rita Grandori (Università degli Studi di Milano-Bicocca)
The possibility to preserve non-covalent interactions during mass spectrometric detection of macromolecules has opened exciting new perspectives in folding and binding studies. Although the forces that act on molecular structures in the gas phase are different from those in aqueous solutions, experiments and theory indicate that it is possible to detect native-like protein conformers and assemblies after ionization and desolvation by mass spectrometry. Results by nano-electrospray-ionization mass spectrometry (nano-ESI-MS) on these topics will be presented.
Reference proteins such as cytochrome c, myoglobin, ubiquitin and lysozyme have been used for the investigation of conformational effects in protein spectra.
Three other systems will be discussed as examples of non-covalent complexes: the hexameric arginine repressor (ArgR), the dimeric beta-lactoglobulin (BLG), and the tetrameric flavodoxin-like protein WrbA. The first one illustrates detection of complexes that are stabilized in solution exclusively by hydrophobic interactions. The second one describes the pH-dependent behavior of the protein in the pH range 2-11. The third one shows analysis of linked protein-protein and protein-ligand binding equilibria.