- High resolution electrospray ionization
- Fourier transform mass spectrometry (FTMS)
- Gas-phase protein conformation and protein
folding - Electrospray MS of conducting polymers
- Multidimensional FTMS of mixtures
- B. S., Indiana University (1989)
- Ph.D., The Ohio State University (1993)
- Postdoctoral Associate, Cornell University (1993-1995)
- Adjunct Assistant Research Professor of Chemistry, Roswell Park Cancer Institute (1996-1998)
- Adjunct Assistant Research Professor of Molecular and Cellular Biophysics, Roswell Park Cancer Institute (1998-present)
- Adjunct Faculty, Dept. of Structural Biology, University at Buffalo (2001-present)
- Research Award, American Society for Mass Spectrometry (Exxon Education Foundation), 1998
Miniaturized electrospray ionization mass spectrometry; mass spectrometry in proteomics; on-line separations coupled to mass spectrometry; mass spectrometry of conducting polymers; biomarker detection; ion dissociation.
The general objective of our research is to obtain structural information of macromolecules (particularly proteins) with electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI). En route to achieving this broad goal, we have developed miniaturized approaches for electrospray ionization (nanospray) and sample preparation protocols for MALDI.
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) . LC-MS/MS is a powerful technique for obtaining primary sequence information of proteins and other biological molecules, whereby precursor ions are mass-selected and then subsequently dissociated to form product ions that reflect the original molecular structure. Processes such as proteolysis (where a protease enzyme "clips" a protein into smaller segments), affinity labeling of enzymatic active-sites (where a certain molecule selectively and irreversibly binds covalently to a reactive site in an enzyme), and production of recombinant proteins occur in complex biological matrices involving many components. Analysis of an analyte of interest in these mixtures by ESI can be greatly facilitated by removal of salts and isolation of individual matrix components. LC is ideally coupled to ESI because both share optimal performance at similar flow rates; furthermore, microcolumn LC has enhanced mass sensitivity vs. normal LC, while removing salts and buffers which may inhibit ESI. We are developing instrumentation for coupling the so-called "nanospray" technique to capillary separations processes, including capillary electrophoresis.
The main thrust of our work in this area is applied research which combines LC and MS/MS for: unraveling the nature and sites of protein heterogeneity; quality control analysis of recombinant enzymes; structural determination of biological markers which may be indicative of disease and conditions ranging from autism to respiratory distress; and identifying active sites of proteins (of known sequence) that have been selectively modified by affinity labels. We are particularly interested in utilizing such methodology in the identification of nucleotide binding sites for enzymes that bind ATP. We are also interested in using this technology for quantitative pharmaceutical applications.
Mass Spectrometry of Polymers . Some of the most interesting yet difficult to analyze industrial polymers are those that conduct electricity, e.g., polyanilines. Such polymers tend to be highly conjugated and are relatively nonpolar. Recent work by Van Berkel and colleagues shows that even nonpolar compounds are amenable to ionization by electrospray using solution-phase redox chemistry. Hence, we are developing electrospray redox approaches in the analysis of conducting, nonpolar polymers; this includes coupling gel permeation chromatography on-line directly with electrospray for the analysis of these industrially-relevant compounds. We are also interested in using ESI-MS and MALDI to examine silicone polymers used as biomaterials.
Selected Recent Publications