Fibrous proteins - silk as a model system

The repetitive nature of fibrous proteins leads to regular secondary and higher order structures. This attribute suggests that these polymers are useful models to gain insight into structure-function relationships. Genetic variants of these proteins can be constructed from precisely defined synthetic oligonucleotides to encode the specific sized protein of interest. The biosynthesis and assembly of this type of protein is addressed using spider dragline and silkworm cocoon silks. This review includes an overview of: (a) spider dragline silk composition and genetics, and (b) the assembly of silk proteins, including the formation of mesophases and control of crystalline structure. Silks are environmentally stable, yet biodegradable under appropriate conditions, leading to a wide range of potential applications for these polymers. (C) 1998 Elsevier Science Limited. All rights reserved.