Academic Title: Associate Professor
Office: LM 512B
Research Homepage: http://www.chem.utoronto.ca/staff/JOCKUSCH/OO_Home.html
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.
M.W. Forbes, A. M. Nagy and R.A. Jockusch, "Photofragmentation of and Electron Photodetachment from a GFP Model Chromophore in a Quadrupole Ion Trap," Int. J. Mass Spectrom., 2011, in press, DOI: 10.1016/j.ijms.2011.08.016.
H. Yao, J.D. Steill, J. Oomens and R.A. Jockusch, "Infrared Multiple Photon Dissociation Action Spectroscopy and Computational Studies of Mass-Selected Gas-Phase Fluorescein and 2’,7’-Dichlorofluorescein Ions," J. Phys. Chem. A, 2011, in press, DOI: 10.1021/jp201946a.
S.K. Sagoo and R. A. Jockusch, "The Fluorescence Properties of Cationic Rhodamine B in the Gas Phase," J. Photochem. Photobiol. A, 2011, 220, 173-178.
F.O. Talbot, A. Rullo, H. Yao and R. A. Jockusch, "Fluorescence Resonance Energy Transfer (FRET) in Gaseous, Mass-Selected Polyproline Peptides" J. Am. Chem. Soc., 2010, 132, 16156-16164.
P.D. McQueen, S. Sagoo, H. Yao and R. A. Jockusch, "On the Intrinsic Photophysics of Fluorescein," Angew. Chem. Int. Ed., 2010, 49, 9193-9196.
V. A. Braz, M. D. Barkley, R. A. Jockusch and P. L. Wintrode, "Efavirenz Binding Site in HIV-1 Reverse Transcriptase Monomers," Biochemistry, 2010, 49, 10565-10573.
M. W. Forbes and R. A. Jockusch, “Gas-phase Fluorescence Excitation and Emission Spectroscopy of three Xanthene Dyes (Rhodamine 575, Rhodamine 590 and Rhodamine 6G) in a Quadrupole Ion Trap Mass Spectrometer,” J. Am. Soc. Mass Spectrom., 2011, 22, 93-109.
Q. Bian, M. W. Forbes, F. O. Talbot and R. A. Jockusch, “Fluorescence Excitation and Emission Spectroscopy of Trapped, Mass-Selected Gas-Phase Ions,” Phys. Chem. Chem. Phys., 2010, 12, 2590-2598.
M. W. Forbes and R. A. Jockusch, “Deactivation Pathways of a GFP Chromophore Studied by Electronic Action Spectroscopy,” J. Am. Chem. Soc., 2009, 131, 17038-17039.
M.W. Forbes, F. O. Talbot and R. A. Jockusch, “The Spectroscopy of Ions Stored in Trapping Mass Spectrometers” book chapter in Practical Aspects of Trapped Ion Mass Spectrometry, Volume 5, R.E. March and J. F. J. Todd, eds.; CRC Press: Boca Raton, FL, 2009, pp 239-290.
M. W. Forbes, M F. Bush, N. C. Polfer, J. Oomens, R. C. Dunbar, E. R. Williams and R. A. Jockusch “Infrared Spectroscopy of Arginine Cation Complexes: Direct Observation of Gas-phase Zwitterions,” J. Phys. Chem. A, 2007, 111, 11759-11770.
M. F. Bush, M. W. Forbes, R. A. Jockusch, J. Oomens, N. C. Polfer, R. J. Saykally, E. R. Williams “Infrared Spectroscopy of Cationized Lysine and ε-N-methyl-lysine in the Gas Phase: Effects of Alkali Metal Ion Size and Proton Affinity on Zwitterion Stability,” J. Phys. Chem. A, 2007, 111, 753-7760.