Multiscale peptide self-assembly

Here, we demonstrate a hierarchical peptide self-assembly process from the nanometer to the micrometer scale. The process begins by mixing a short hydrophobic peptide and a longer $\alpha$-helix peptide. Cross-$\beta$ nanostructures spontaneously form that then aggregate into nanometer fibrils and then micron-sized fibers. FT-IR and Raman spectroscopy show unraveling of $\alpha$-helices and packing of aliphatic side groups as the major events leading to $\beta$-sheet and large fiber formation. A thermodynamic model is presented that uses conformational change and hydrogen bond formation to describe free energy change.