Wednesday Morning Session Preview: H/D Exchange: Biological Applications

Wednesday, 8:30-10:30 am, Room 103

The first presentation will be given by Roxana E. Iacob of Northeastern University and will discuss the influence of adnectin on the extracellular domain of epidermal growth factor receptor (EGFR) as measured by hydrogen–deuterium exchange mass spectrometry. Adnectins bind to the extracellular portion of EGFR and block its activity by inhibiting its phosphorylation, and therefore are potential therapeutic agents to cancer modulation. Full length extracellular EGFR alone and bound to adnectin were probed with hydrogen–deuterium exchange mass spectrometry (HDX-MS) and the effects of binding were identified.

Modupeola Sowole of the University of Western Ontario, in London, Canada, will present the second talk, entitled, “Effector Binding Causes Major Changes in the Structure and Dynamics of the ClpP Protease Complex: A HDX/MS Investigation.” Acyldepsipeptides (ADEPs) represent a new class of antibacterial drugs that bind ClpP — a multiprotein complex that is part of the bacterial proteolytic machinery — and turn the protein in an unregulated protease. ADEP-mediated activation of ClpP involves large structural changes. However, many details of this activation mechanism remain unclear. HDX-MS has been used to gain a better understanding of this mechanism.

The binding of antibodies to hepatitis B virus capsids is the subject of the third presentation, by Jessica Bereszcza of the Biomolecular Mass Spectrometry and Proteomics group at Utrecht University, in The Netherlands. This study focused on the Fab fragments of two monoclonal antibodies, E1 and 3120. The investigators used HDX-MS to investigate the effects on a capsid protein, HBcAg, of binding these antibodies.

Shaolong Zhu of York University in Toronto, Canada will give the fourth talk, on the characterization of residual structure in the native and amyloidogenic tau, to aid in understanding mechanistic processes in in tau amyloidogenesis in Alzheimer’s disease. The study results indicate the transition from globular to more expanded conformation of the protein. In addition, it appears that a secondary structure in a neighboring region is formed and stabilized as the hexapeptide motifs becomes more disordered.

The fifth talk, by David Marciano of the Scripps Research Institute in Jupiter, Florida, will cover the rational design of a novel antidiabetic therapeutic guided by HDX. Differential HDX is an emerging approach for characterizing ligand-induced changes to protein conformation and dynamics. Marciano’s group has developed high throughput instrumentation and software enabling the rapid collection and processing of online digested, multiple replicate, differential HDX data with statistical analysis. Here, they report the application of this platform to screen large numbers of ligands targeting the nuclear receptor PPARG (peroxisome proliferator-activated receptor gamma). These efforts have provided important mechanistic insights enabling the rational design of a novel class of insulin sensitizers for the treatment of type 2 diabetes mellitus.

George M. Bou-Assaf of the biopharmaceutial company Biogen Idec, in Cambridge, Massachusetts, will wrap up the session. He will discuss the higher-order structure characterization of a fusion protein biopharmaceutical for hemophilia A by HDX-MS. HDX-MS provides relatively high-throughput, high-resolution structural data of biopharmaceuticals that is otherwise unavailable by other techniques.