Associate Professor
B.S. College of William and Mary Ph. D. University of North
Carolina, Chapel Hill NRC postdoctoral fellowship - Naval
Research Laboratory
Bioanalytical Chemistry
Analytical chemistry, mass spectrometry, protein folding, metal-protein interactions, gas-phase chemistry, nanomaterials.
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Principal Research Interests
Proteins are essential players in most biological processes and unraveling their behavior (or
misbehavior) is important for understanding the molecular basis of life and of a variety of diseases. My research group is interested in protein chemistry with a particular focus on the development of new methods to gather insight into protein misfolding and aggregation, protein interactions with metals, and protein chemistry within a cell. We have two primary areas of investigation: (1) mass spectrometry-based methods to study protein amyloid formation and (2) nanomaterials as novel extraction/concentration/detection methods for protein analyses in complex mixtures.
An increasing number of proteins are known to form amyloid fibrils in vivo, and the formation of these fibrils is implicated in several diseases (e.g. Alzheimer’s, Parkinson’s). One of these proteins, β-2-microglobulin (β2m), can form amyloid fibrils, and these fibrils are the main pathogenic process underlying dialysis-related amyloidosis (DRA). Like other amyloid systems, β2m fibril formation proceeds by partial protein unfolding, subsequent oligomerization, and eventual elongation to form mature fibrils. While aspects of general amyloid formation are understood, molecular-level information about the early stages of the amyloid reaction is lacking for almost all amyloid systems; however, this information is critical for the rational design of therapeutics against amyloid diseases. We strive to obtain amino acid-level information of the unfolding and oligomerization of β2m prior to fibril formation by developing mass spectrometry-based methods with the necessary temporal and spatial resolution. We are particularly interested in the role that Cu(II) plays in the amyloid formation of β2m. In general, the methods that we develop not only provide insight into β2m’s amyloidosis but are also general enough to work for other amyloid systems.
Nanomaterials have great potential for enhancing protein analysis in complex mixtures. We use functionalized nanomaterials as new extraction/concentration/detection methods that can more fully exploit the exquisite sensitivity and specificity of mass spectrometry. The “bottom-up” design control of these materials from the molecular level to the micron/millimeter level makes them adaptable tools for coupling with mass spectrometry. Together with mass spectrometry, these nanomaterials are being used in several contexts: (1) to extract proteins and peptides in complex mixtures with high selectivity and efficiency; (2) to fractionate protein and peptide mixtures according to desired chemical or physical properties; (3) to facilitate protein identification in complex mixtures; and (4) to detect compounds of interest in cell lysates and whole cells.
Representative Publications
“Cu(II) Organizes ß-2-Microglobulin Oligomers but is Released Upon Amyloid Formation,” K. Antwi, M. Mahar, R. Srikanth, M.R. Olbris, J.F. Tyson and R.W. Vachet, Prot. Sci. (2008) in press.
“Polymeric Inverse Micelles as Selective Peptide Extraction Agents for MALDI-MS Analysis,” M.Y. Combariza, E.M. Savariar, D.R. Vutukuri, S. Thayumanavan and R.W. Vachet, Anal. Chem. 79, 7124-7130 (2007).
“Mixed Monolayer-Protected Gold Nanoclusters as Selective Peptide Extraction Agents for MALDI-MS Analysis,” B.N.Y. Vanderpuije, G. Han, V.M. Rotello and R.W. Vachet, Anal. Chem. 78, 5491-5496 (2006).
“Transition Metal-Peptide Binding Studied by Metal-Catalyzed Oxidation Reactions and Mass Spectrometry,” J.D. Bridgewater, J. Lim and R.W. Vachet, Anal. Chem. 78, 2432-2438 (2006).
Click Here for a complete list of publications.
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