Professor John P. Simons FRS

Biomolecules in the Gas Phase

In the last few years, using strategies “borrowed” from chemical physics and quantum chemistry, it has become possible to explore the architectures of small, (and not so small) bioactive molecules and of individual biomolecular building blocks, both neutral and ionic, and to characterise quantitatively, the local molecular interactions that determine their structures - in the gas phase(1).

This has come about through the development of techniques such as laser ablation, for transferring them into the gas phase; the availability of rapid cooling techniques (free jet expansion or trapping in large helium clusters) to stabilise their conformers and/or clusters; highly selective and sensitive combinations of laser-based optical spectroscopy, coupled with mass spectrometry, to probe their structures; and the ready accessibility of powerful ab initio quantum chemical computational codes for their interpretation.

The range of bio-molecules that have been structurally assigned (both isolated and in hydrated clusters) now includes neurotransmitters(1), amino acids(1,2), amides(1), small peptides(1), nucleic acid bases(3), the nucleoside, guanosine(4) and (a very recent “break-through”), the glycoside, phenyl beta-D-glucopyranoside(5) opening the way to future studies of many other sugars and model glycopeptides.

1. E.G.Robertson and J.P.Simons, PCCP, 2001, 3, 1.
2. R.T.Kroemer, M.R.Hockridge, L.C.Snoek and J.P.Simons, PCCP, 2001, 3, 1819.
3. E.Nir, Ch.Janzen, P.Imhof, K.Kleinermanns and M.S.de Vries, PCCP, 2002, 4, 732, 740.
4. E.Nir, P.Imhof, K.Kleinermanns and M.S.de Vries, JACS, 2000, 122, 8091
5. F.Talbot and J.P.Simons, PCCP, 2002, submitted.