Spider silk assembly control

In man-made fibres, any stretching will irreversibly alter the crystallinity and there is no control of the lateral size of polymer crystals. Semicrystalline polymer networks typically consist of platelet type crystals whose width exceeds their thickness by several order of magnitudes because only the thickness is controlled by the chain folding [61]. In contrast to synthetic fibres, spider silk does not need any mechanical treatment by external forces the constituents self-assemble directly during the spinning-process. These examples clearly demonstrate the need for more detailed control of the mesoscopic structures for further development of man-made materials. 

Winkler S, et al. (1999) Designing Recombinant Spider Silk Proteins to Control Assembly. Int. j. biol. macromol. 24 p. 265-70. 

Hagn, F., Eisoldt, L., Hardy, J., Vendrely, C., Coles, M., Scheibel, T., and Kessler, H. (2010). A conserved spider silk domain acts as a molecular switch that controls fibre assembly. Nature in press. 

Winkler, S., Szela, S., Avtges, R, Valluzzi, R., Kirschner, D. A., and Kaplan, D. (1999). Designing recombinant spider silk proteins to control assembly. Int. J. Biol. Macromol. 24, 265-270. 

Chimeric (fusion) proteins that incorporate the R5 peptide have been synthesized to control and precipitate silica nanoparticles. Po Foo and coworkers have utilized a two-component chimeric protein consisting of the R5 polypeptide (from C. fusiformis) and the self-assembling domain based on the consensus repeat in the major ampullate spidroin protein 1 (MaSpl) of Nephila clavipes spider dragline silk [64]. MaSpl forms highly stable P-sheet secondary stmctures that can be spun into intricate fibers which, when fused with the sihca-templating R5-peptide, allow for the formation of film-like and fibrous silica structures (Figure 1.18). 

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