Conformation of Spider Silk Proteins In Situ in the Intact Major Ampullate Gland and in Solution

• Published in: Biomacromolecules Vol. 8; no. 8; pp. 2342 - 2344
• Main Authors: Lefèvre, Thierry, Leclerc, Jérémie, Rioux-Dubé, Jean-François, Buffeteau, Thierry, Paquin, Marie-Claude, Rousseau, Marie-Eve, Cloutier, Isabelle, Auger, Michèle, Gagné, Stéphane M, Boudreault, Simon, Cloutier, Conrad, Pézolet, Michel
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 13-08-2007
• Subjects: Applied sciences; Arachnida; Araneae; Araneus diadematus; Biochemistry. Physiology. Immunology; Biological and medical sciences; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Invertebrates; Natural polymers; Nephila clavipes; Physicochemistry of polymers; Physiology. Development; Proteins; In situ; Araneida; Nephila clavipes; Araneus diadematus; Arachnida; Silk; Silk gland; Arthropoda; Animal protein; Helical structure; Aqueous solution; Invertebrata; Araneidae; Conformation
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm7005517

To understand the spinning process of dragline silk by spiders, the protein conformation before spinning has to be determined. Raman confocal spectromicroscopy has been used to study the conformation of the proteins in situ in the intact abdominal major ampullate gland of Nephila clavipes and Araneus diadematus spiders. The spectra obtained are typical of natively unfolded proteins and are very similar to that of a mixture of recombinant silk proteins. Vibrational circular dichroism reveals that the conformation is composed of random and polyproline II (PPII) segments with some α-helices. The α-helices seem to be located in the C-terminal part whereas the repetitive sequence is unfolded. The PPII structure can significantly contribute to the efficiency of the spinning process in nature.