Professor Richard Vachet

Professor Richard Vachet
Department of Chemistry
University of Massachusetts Amherst

Protein Structure, Binding, and Aggregation in Complex Mixtures

Characterizing the higher-order structures (HOS) and interactions of proteins in complex mixtures is challenging and requires the development of new tools. Mass spectrometry (MS)-based techniques are emerging as valuable tools in structural biology, and among these tools covalent labeling (CL) methods have some unique advantages that can be exploited to study protein structure, protein interactions, and protein aggregation, including in live cells. In CL-MS, HOS and binding information are encoded via the formation of covalent bonds that can survive the many steps (i.e. cell lysis, extraction, digestion, separation, MS/MS) needed to analyze proteins by MS. We are developing and applying new CL-MS methods to study the pre-amyloid forms of two important amyloid systems. One is β-2-microglobulin (β2m), which forms amyloids in dialysis-related amyloidosis. The second is Tau, which is important in various tauopathies such as Alzheimer’s disease. We are also developing an approach that can study Tau binding to the low-density lipoprotein receptor-related protein 1 (LRP1) in live cells. In our work on β2m, we have used CL-MS to characterize the initial amyloidogenic change that this protein undergoes and have mapped the energy landscape of this structural change. In addition, we have used CL-MS to determine the structures of pre-amyloid oligomers that have led to the development of small- molecule inhibitors that prevent β2m amyloid formation. Our work on Tau is focused on understanding the transition of this structurally disordered protein into ordered aggregates, and we have also recently been studying its interaction with LRP1, which is a membrane-associated receptor that is a critical determinant for Tau spread and aggregation. To study the ordering of Tau’s structure as it aggregates, we use native MS to monitor its conformational heterogeneity over time. Tau binding to LRP1 relies on CL-MS based mapping of this protein-receptor interaction on live H4i neuroglioma cells. Tau-LRP1 interactions promise to reveal potential approaches for drug intervention for Tau uptake.

Richard Vachet

Richard Vachet is a Professor in the Chemistry Department at the University of Massachusetts Amherst. He received a Ph.D. in Analytical Chemistry from the University of North Carolina- Chapel Hill and did postdoctoral research at the US Naval Research Laboratory from 1997 to 1999 as a National Research Council Postdoctoral Research Associate. He began his independent career at the University of Massachusetts Amherst in 1999. His current research focuses on (a) the development and application of mass spectrometry-based methods to study protein amyloid formation; (b) the development of new tools to study the higher order structure of protein therapeutics; and (c) the detection and imaging of nanomaterial drug delivery agents in biological systems. He has published over 180 peer-reviewed journal articles and has been a member of the Editorial Board of the Journal of the American Society for Mass Spectrometry and the Features Panel for Analytical Chemistry. He has also won several awards, including the Outstanding Research Award from the University of Massachusetts Amherst, the GlaxoSmithKline Lectureship in Analytical Chemistry, and the Young Investigator Award from the American Society for Mass Spectrometry.

Hosted by Professor Varun Gadkari