Characterication of aggregate gland silk factor 1
Spider silk is a high performance fiber with extraordinary mechanical properties, including high tensile strength and toughness. Due to these outstanding material properties, scientists are rapidly pursuing the production of synthetic spider silks for a variety of different applications. In these studies, we characterize the aggregate gland specific factor 1 (AgSF1) from the black widow spider, Latrodectus hesperus. After the development of an anti-AgSF1 polyclonal antiserum, we demonstrate by western blot analyses that the AgSF1 protein is highly expressed in the aggregate gland and the protein is localized to the connection joints of cobweaver webs. We also overexpress and purify two different recombinant AgSF1 fusion proteins, named AgSF1G and AgSF1G+GXPXP. These recombinant proteins encompass different regions within the AgSF1 amino acid sequence. Using wet-spinning methodology we also demonstrate that these proteins can be spun into synthetic silk fibers. Mechanical studies and ultrastructure analyses of the synthetic fibers reveal tensile strengths and toughness values that are below natural dragline silk fibers. Secondary structural analyses of the AgSF1 recombinant proteins in solution using circular dichoism reveal the N-terminal region of AgSF1 is alpha helical in nature. Collectively, these studies advance our understanding of silk proteins that are expressed in the aggregate gland and support that these proteins play an important role in prey capture in cobweavers.
Molecular biology, Biological sciences, Biology
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