Membrane-Protein Interaction at the Single Molecule Level
Understanding the interaction between membranes and amyloid protein oligomers is a key unsolved challenge in the field of antimicrobial peptides and amyloid diseases such as Alzheimer’s and Type II diabetes. While the structure of the membrane-bound monomeric subunit is slowly emerging from bulk studies, we need to know how many monomers make up the oligomer, whether this species subsequently grows to specific sizes, whether specific membrane architectures determine binding, and whether interaction with other membrane proteins substantially alter their statistics. Here we approach this problem by the interaction of amylin and amyloid beta with artificial lipid bilayers. We perform single molecule photobleaching experiment with Total Internal Reflection Fluorescence Microscope to probe the stoichiometry. We also employ an atomic force microscope to probe changes in membrane rheology. Our answers may be significant consequences for the underlying toxic mechanism.