Crystal and molecular structures of raw bivoltine silk fibre—A comparative study

Abstract

Crystal and molecular structural analysis of raw bivoltine silk fibre (Bombyx mori) has been made using Linked-Atom Least-Squares technique. It is observed that the unit cell consists of four molecular chains with the space unit cell parameters (a=9.4Å, b=9.2Å and c(fibre axis)=6.97Å with =90o) and the space group P21. The molecular modification is essentially same as β-pleated structure with antipolar-antiparallel arrangements formed by hydrogen bonds. The essential differences observed in structure, such as intermolecular distance and fractional coordinates, are discussed in detail in comparison with crystal structure of raw pure Mysore silk fibres.