Under these circumstances, Keio University, RIKEN, Kyoto University, Spiber Inc. and others have comprehensively analyzed the constituent proteins of four spider silks of the subfamily Nephila clavata, and spider silk has been considered more than ever. It was revealed that it is a complicated composite material.Then, by blending the protein contained in the newly identified spider silk into the artificial spider silk material, we succeeded in dramatically improving the physical characteristics of the spider silk material.

　The four species closely related to Nephila clavata (Nephila pilipes, Nephila pilipes, Nephila pilipes, and Nephila pilipes), which were the subjects of this study, are spiders with particularly excellent toughness (threads used when spiders hang or move). There is even spinning.As a result of performing multi-omics analysis after determining these genomes, not only the thread proteins "MaSp4" and "MaSp1" that were previously known as genes constituting spider traction threads, but also the new "MaSp2B" is rather. It was identified as a major component.In addition to the thread protein, several proteins of unknown function were found. Among them, the protein named "SpiCE (Spider-silk Constituting Element)" showed extremely high gene expression in the abdomen of the spider that synthesizes the traction thread.

　The research group also experimentally proved that the addition of these novel proteins to artificial spider silk contributes to the improvement of physical properties.Surprisingly, adding just 1% of SpiCE per weight increased Tensile strength by more than double and Elongation by more than 2 times.

　This result is expected to greatly contribute to the promotion of future development of artificial protein materials by clarifying a part of the mechanism of high-performance expression of artificial spider silk.

Paper information:[Proceedings of the National Academy of Sciences] Multi component nature underlies the extraordinary mechanical properties of spider dragline silk