IDENTIFICATION AND ANALYSIS OF PROTEINS IN SPIDER TUBULIFORM SILK

Spiders contain 7 different silk-producing glands that produce high performance threads. Because these fibers have extraordinary mechanical properties, it has attracted the attention of scientists across the globe. One gland, which is referred to as the tubuliform gland, manufactures the fibroins Tubuliform Spidroin 1 (TuSp1), Egg Case Protein 1 (ECP-1) and Egg Case Protein 2 (ECP-2). One of the primary functions of tubuliform silk is to protect eggs from the environment. Scanning electron microscopy studies reveal that egg cases or sacs are composed of different silk types: tubuliform and aciniform silk. We hypothesize the egg sacs contain additional, uncharacterized proteins. In order to identify new proteins in egg sacs, we collected egg sacs spun from female black widow spiders, carefully removing the eggs. The fibers were dissolved in urea to denature the proteins, subject to alkylation using iodoacetamide, and then digested with trypsin. Tryptic peptides were separated using nano high performance liquid chromatography and analyzed by MS and MS/MS analysis using an Orbitrap Fusion mass spectrometer. MS and MS/MS spectra were analyzed using the Proteome Discoverer 2.1 software. Several novel proteins were discovered as constituents of egg sacs