Open Access Thesis
Master of Science (MS)
Department or School
Deborah Heyl-Clegg, PhD, Chair
A key factor in the development of type II diabetes is the loss of insulin-producing pancreatic beta cells. The amyloidogenic human Islet Amyloid Polypeptide (hIAPP, also known as human amylin) is believed to play a crucial role in this biological process. Previous studies have shown that hIAPP forms small aggregates that kill β-cells by disrupting the cellular membrane. In this study we report membrane fragmentation by hIAPP20-29 and the rat version, rIAPP20-29, using solid-state NMR experiments on nanotube arrays of anodic aluminum oxide containing aligned phospholipid membranes.
31P NMR results suggest that membrane fragmentation by hIAPP is related to peptide aggregation as the presence of Congo red, an inhibitor of amyloid formation, prevented membrane fragmentation, and the non-amyloidogenic rat IAPP did not cause membrane fragmentation. DSC studies suggest membrane disordering is caused by both fragments of peptides, possibly due to extensive aggregation on the surface. 13C-1H NMR results suggest that rIAPP20-29 causes transient deformations of the bilayer by intercalating into the hydrophobic core. Last, dye leakage experiments indicate that both peptides induce membrane permeability, although a greater effect is seen for the hIAPP.
Samisetti, Shyamprasad, "Membrane fragmentation by a 20-29 fragment of human islet amyloid polypeptide and rat amyloid polypeptide" (2007). Master's Theses and Doctoral Dissertations. 8.