CHARACTERIZATION OF AMYLIN PEPTIDE OLIGOMERIZATION BY EXPERIMENTAL TECHNIQUES

A wide range of proteomic studies shows that more than a third of proteins in eukaryotic organisms exhibit intrinsically disordered behaviour in specific regions or throughout their entire structure. These proteins can adopt various conformations, including a beta-sheet-like structure, and can stack on top of each other to form amyloid fibers. These amyloid fibers often gather in plaques in human tissue and are associated with various diseases. One example is the aggregation of the amylin peptide (or hIAPP) in pancreatic tissue, forming amyloid fibrils associated with type 2 diabetes mellitus (T2DM). hIAPP is a 37-residue peptide produced by beta cells in Langerhans islets, and its dysfunction is related to T2DM, but the causes, mechanisms of aggregation, and chemical pathways are not yet fully understood.

This work aims to elucidate the mechanisms of hIAPP fibrillation and characterize the peptide in solution. To this end, we investigate its oligomerization through a combination of in vitro characterization techniques. Because hIAPP is an extremely aggregation-prone system, advanced methods have been employed and be shown to separate the different populations and thereby identify the various species present in solution, including SEC-SAXS (size-exclusion chromatography coupled with small-angle X-ray scattering) and DOSY NMR (diffusion-ordered nuclear magnetic resonance spectroscopy), together with more conventional characterization techniques such as synchrotron radiation circular dichroism (SRCD) and ThT fluorescence.