CONFORMATIONAL CHANGE OBSERVED IN THE COURSE OF FLOW-INDUCED CRYSTALLIZATION OF Bombyx mori SILK FIBROIN

Conformational change of silk fibroin coagulated from the aqueous solution by the mechanical stirring was examined by means of infrared spectroscopy, circular dichroism and x-ray diffractometry. The silk fibroin obtained by flow-induced crystallization showed unoriented molecular form “silk II” structure, nevertheless of the applying of shears with various rates and time intervals. In contrast, the silk fibroin obtained by the casting from the supernatant solution and/or the residual silk fibroin in the solution exhibited β-structure, of which content increased with increasing shear rate.