Research Topics
Molecular conformation plays a crucial role in the function and selectivity of biologically and pharmacologically important molecules. The last few years have seen a very rapid growth of spectroscopic and computational studies exploring the conformational and structural landscapes of neutral and protonated biomolecules, their dimers and molecular complexes, isolated in the gas phase, in order to characterize their conformational and supramolecular structures. They include neurotransmitters, amino acids, amides and oligo-peptides, nucleic acid bases and carbohydrates, determined principally through laser-based vibrational spectroscopy in combination with density functional theory and ab initio calculations. These provide direct, bond-specific information about local interactions, particularly those involving hydrogen bonding. OH and NH stretch bands in free amino acids, in peptide amino acid residues, and especially in carbohydrates, oligosaccharides and their hydrated complexes, are extraordinarily sensitive to their local H-bonded environments, reflecting local and cooperative interactions as well as secondary and supramolecular structures. It should alsobe possible to use the local carbohydrate CH stretch bands to probe the dispersion forces which support the stacking interations with aromatic amino residues, often involved in selective protein-carbohydrate molecular recognition processes.
Current research includes structural investigations of carbohydrates, including mono- and oligosaccharides, neutral and protonated peptides and glycopeptides (in collaboration with Profs B G Davis and D C Clary) as well as their hydrated and molecular complexes, conducted under molecular beam conditions, using vibrational spectroscopy in the mid IR [reflecting local OH, NH and CH modes] and in the 'fingerprint region' at the FOM Institute ('FELIX'). We are concerned particularly, with their relation to biologically important processes, such as molecular recognition and with establishing links between their gas phase structures and those determined in solution in collaboration with Prof Laurence Barron at Glasgow.