Recombinant Shematrin: Silk-Like Protein From the Ocean

Shematrins are glycine-rich proteins originally derived from the pearl oyster Pinctada fucata, and they are suggested to be given as organic matrix proteins for calcification. We noticed that shematrins contain repetitive silk-like peptides, which are similar with those of spiders and silkworms. Especially, we chose shematrin-5, which has Gly-Gly-(Lys/Tyr) repeat, as our target. This domain is thought to build up 3₁-helix secondary structure and thus, it might show remarkable extensibility when formulated by appropriate methods such as wet spinning and film casting. In the present work, we constructed recombinant Escherichia coli system carrying the codon-optimized gene of hexahistidine-fused shematrin-5. We successfully expressed and purified recombinant shematrin-5 silk-like protein for wet-spun fiber formation and measurement of its mechanical properties. We expect that production and formulation of recombinant shematrin may give a source for researchers to study its role in biomineralization process and mechanical functions in nature. Moreover, we expect to use this marine silk in various application areas including medical and textile industries.