Biomimetic manufacturing of customised novel fibre proteins for specialised applications

Using spider silk and collagen as a model, we have investigated the role that various protein primary structural components play in fibre production. Spidroins, spider dragline silk protein components, are essentially characterised by an amino-acid repeat containing a glycine-rich motif (amorphous) followed by an alanine-rich motif (crystalline, putatively responsible for fibre strength). We have tested the importance of alanine runs in these proteins and the role of this motif in the mechanical properties of the resulting fibre. To test the importance of alanine-rich motifs in the spidroin-1 proteins, we engineered three types of spidroin-1-like genes containing sequence encoding for different amounts of alanine repeats in the protein (normal, low, and no alanine residues). We also have engineered three copolymer collagen-spidroin-1 genes using each of the three spidroin-1 synthetic genes. These copolymers were mimicked on the existing natural block collagen-silk-like protein copolymer found in the byssus thread of marine mussels. All of these constructs were introduced in yeast (Pichia pastoris) for protein production. We are currently purifying each of the recombinant proteins for structural analysis (CD-spectroscopy).