Spider Dragline Silk Contains Water Soluble Proteins

Modern society recognizes that spider silk has a greater toughness than Kevlar, which has induced many labs around the world to research the components, mechanical properties, and artificial reproduction of spider silk. The two major silk proteins found in dragline silk are MaSp1 and MaSp2 (Major Ampullate Spidroin 1&2), which are very large, insoluble proteins that compose a majority of the spider silk. Most labs have been partially successful at artificially recreating spider silk by using only MaSp1 and MaSp2. In our experiment with Lactrodectus hesperus (Black Widow Spiders), we wanted to determine whether there are water soluble proteins on the surface of the natural spider silk, which other labs have not explored. In our studies, native silk was collected, washed with water, and the resulting water fraction was digested with both trypsin and glu-C. Finally, the protease digest was analyzed by nano-LC MS/MS and the following water soluble proteins were discovered: AcSp1, Aqueous glue droplet peptide, Putative uncharacterized protein, and SST 241 uncharacterized protein. The identification of AcSp1 in the water fraction might suggest that it could be used for artificial fiber production by wet spinning methodologies that are based on water solvents