Spider Silk Proteins – Mechanical Property and Gene Sequence

Abstract

-Spiders spin up to seven different types of silk and each type possesses different mechanical properties. The reports on base sequences of spider silk protein genes have gained importance as the mechanical properties of silk fibers have been revealed. This review aims to link recent molecular data, often translated into amino acid sequences and predicted three dimensional structural motifs, to known mechanical properties.

The elaborate structure of spider silk

“…Spider silk primarily consists of proteins that possess large quantities of nonpolar and hydrophobic amino acids like glycine or alanine, but for example, no or only very little tryptophan. 4,13,14 In comparison to common cellular enzymes, it is evident that silk proteins exhibit a quite aberrant amino acid composition ( Fig. 2A).…”

“…Several studies describe these regions to adopt amorphous rubber-like structures, 20,21 whereas others suggest formation of a 3 1 -helical structure. 18 Flagelliform silk, typically rich in GPGGX and GGX motifs, preferably folds into β-turn structures resulting in a right-handed β-spiral helix upon stacking (13,14,30). 16,22 Apart from the repetitive core domain, nonrepetitive regions are located at the protein's termini.…”

Mimicking biopolymers on a molecular scale: nano(bio)technology based on engineered proteins

“…Their large core domains, in particular, contain highly repetitive amino acid sequences composed of short polypeptide stretches of approximately 10-50 amino acids, which often account for more than 90 per cent of the whole spider silk protein. Alanine-rich blocks are known to form b-sheet structures in assembled fibres being responsible for the high tensile strength of MA silk, whereas glycine-and proline-rich blocks in flagelliform and MA silk presumably form 3 10 -helices and b-turn spirals imparting elasticity, respectively (Hayashi & Lewis 1998;Rising et al 2005;Hardy et al 2008). The non-repetitive terminal domains of the proteins comprise approximately 100-200 amino acids and are hypothesized to play a role in the assembly of spider silk proteins into fibres during spinning (Huemmerich et al 2004a;Exler et al 2007).…”

Polymerization of Peptide Polymers for Biomaterial Applications

“…The strength of this polymer is a result of the highly crystalline structure of the poly(Ala) domains and the amorphous poly(Gly-Gly-Gly-Xaa-Gln-Tyr) repeat is amorphous in structure which allows for flexibility. [33,34] All of three of these high molecular weight polypeptides are composed of highly repetitive amino acid sequences. The present review will be concerned with the synthesis of polypeptides and how they polypeptides will be used in the production of new biomaterials.…”