Self-assembly modifying role of metal ions in silk fibroin

Native silk fibers produced by silkworms exhibit high strength and toughness even compare to some of the top synthetic fibers. However, the silkworm spinning mechanism that allows it to form such tough fibers is not fully understood. It is mostly agreed that the spinning process involves the conformation transition of fibroin, silk main protein, from random coil and α-helix to β-sheet due to the influence of shear forces, elongational flow, metal ions and pH. In this study, we present the influence of some divalent metallic ions on the folding process of silk fibroin and its fibrillation properties.