2019 Volume 27 Pages 95-101
To understand the relationship between structure and mechanical property of silks, it is necessary for understanding their hierarchical structure over wide range of structural scales. In this study, hierarchical structure of Indian golden wild-silk, Antheraea assamensis (A. assama) silk, was investigated by wide-angle and small-angle X-ray scatterings (WAXD and SAXS). SAXS results revealed presence of nanofibril structure made up of periodically repeated β-sheet crystalline and amorphous domains. The correlation function analysis for SAXS data clarified each domain thickness in the periodic structure. The crystalline domain thickness was quantitatively ascribed to the 12 ~ 13 alanine residues in polyalanine blocks and the amorphous one to the roughly 40% slacking non-polyalanine blocks in the tandem repeating motifs of A. assama silk determined recently by Gupta et al. On the basis of quantitative quantitative WAXD and SAXS data, a detailed hierarchical structure model for A. assama silk was proposed.
