A proposed model for dragline spider silk self-assembly: Insights from the effect of the repetitive domain size on fiber properties

Authors

  • Shmulik Ittah,

    1. Department of Cell and Developmental Biology, Silberman Life Sciences Institute, Edmond Safra Campus at Givat-Ram, The Hebrew University, Jerusalem 91904, Israel
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  • Noaa Barak,

    1. Department of Cell and Developmental Biology, Silberman Life Sciences Institute, Edmond Safra Campus at Givat-Ram, The Hebrew University, Jerusalem 91904, Israel
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  • Uri Gat

    Corresponding author
    1. Department of Cell and Developmental Biology, Silberman Life Sciences Institute, Edmond Safra Campus at Givat-Ram, The Hebrew University, Jerusalem 91904, Israel
    • Department of Cell and Developmental Biology, Silberman Life Sciences Institute, Edmond Safra Campus at Givat-Ram, The Hebrew University, Jerusalem 91904, Israel
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Abstract

Dragline spider silk has been intensively studied for its superior qualities as a biomaterial. In previous studies, we made use of the baculovirus mediated expression system for the production of a recombinant Araneus diadematus spider silk dragline ADF4 protein and its self-assembly into intricate fibers in host insect cells. In this study, our aim was to explore the function of the major repetitive domain of the dragline spider silk. Thus, we generated an array of synthetic proteins, each containing a different number of identical repeats up to the largest recombinantly expressed spider silk to date. Study of the self-assembly properties of these proteins showed that depending on the increasing number of repeats they give rise to different assembly phenotypes, from a fully soluble protein to bona fide fibers with superior qualities. The different assembly forms, the corresponding chemical resistance properties obtained as well as ultrastructural studies, revealed novel insights concerning the structure and intermolecular interactions of the repetitive and nonrepetitive domains. Based on these observations and current knowledge in the field, we hereby present a comprehensive hypothetical model for the mechanism of dragline silk self-assembly and fiber formation. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 458–468, 2010.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

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