Nanostructure of natural fibrous protein:: In vitro nanofabric formation of Samia cynthia ricini wild silk fibroin by self-assembling

Atomic force microscopy was adopted to study the nanoscopic structure formation of natural fibrous protein, fibroin from the Samia cynthia ricini wild silkworm. We have observed highly ordered nanoscale textile-fabric-like structures of fibroin molecules. From AFM and SDS-PAGE experiments, it was revealed that fibroin molecules have a rigid rodlike structure and form aggregates by end-to-end interactions of molecules. By analogy with Bombyx mori fibroin, S. c. ricini fibroin is supposed to assemble by electrostatic interactions of molecules.