Identification of New Proteins in Black Widow Spider Egg Case Silk Using Mass Spectrometry

Spider silk has been studied for its potential industrial application. With its high toughness and strength, material scientists predict that spider silk can revolutionize the production of materials used in a variety of applications. In the Western black widow, Latrodectus hesperus, a number of proteins are involved in manufacturing and assembling of silk fibers. Knowing more about the function of each protein involved in the silk production pathway will help researchers understand how to produce fibers on a large scale. Specifically, we are interested in finding proteins involved in egg case silk production. The goal of this study was to identify new proteins present in egg case silk. In order to identify new proteins in egg case silk, we dissolved egg case silk fibers with chaotropic reagents, digested the denatured protein mixture with trypsin, purified the protein fragments, then sequenced the peptide mixture using MS/MS analysis. MS/MS analysis was performed using an Orbitrap Fusion mass spectrometer. MS/MS spectra were searched against the Latrodectus hesperus database using the program Proteome Discover 2.1. After searching the database, MS/MS data revealed that uncharacterized proteins were present in our egg case silk sample. With the discovery of these new proteins we can continue to study the specific structural role they each have in egg case silk, providing more information on how material scientists can replicate this process for industrial applications.