Silks are fibrous proteins that form heterogeneous, semi-crystalline solids.
Silk proteins have a variety of physical properties reflecting their range of functions. The differing physical properties arise from variation in the protein's primary and secondary structure, and their packing in the solid phase. Its mechanical properties, however, are closer to those of silk from Bombyx mori silkworm, which has a different primary structure. Nevertheless, we deal with a multi-spin system and the spin dynamics may be complex. O pairs adjacent in the primary structure.