Our research uses a combination of mass spectrometry and optical spectroscopy to characterize biological molecules in a highly controlled environment - both isolated in the gas phase and in small complexes or clusters. Using these techniques, we can examine the intrinsic properties (such as structure or stability) of isolated biological molecules. Then selected pieces of the local environment (a known number of water molecules, metal ions or binding partners, etc.) can be added back into the system in order to examine the effect of each, separately. These studies provide a bridge between the gas and solution-phase regimes.
In our experimental set-up, gas phase biological ions, complexes or clusters are produced using electrospray ionization (ESI) and then trapped in either a Fourier-transform ion-cyclotron resonance (FT-ICR) mass spectrometer or an electrodynamic ion trap . In addition to traditional trapping mass spectrometry techniques (isolation of ions of the desired mass-to-charge, probing via dissociation reactions or ion/molecule reactions), we are developing gas-phase fluorescence and fluorescence resonance energy transfer (FRET) techniques as a probe of structure.