MOLECULAR MODELING OF SPIDER SILK ELASTICITY

We introduce the first comprehensive molecular model of spider draglin e elasticity which clearly integrates most of the information known to date about the structure of the fiber. In accordance with X-ray evide nce, the dragline is represented by a large number of small crystallit es separated by amorphous regions made of rubber-like chains. Our mode l results clearly indicate the important role of the crystallites whic h act as multifunctional cross-links and create inside the amorphous r egions a thin layer with modulus higher than in the bulk. The role of the crystallites in spider silk is found to be amazingly similar to th at speculated for carbon black in synthesized elastomers.