In situ conformation of spider silk proteins in the intact major ampullate gland and in solution.
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 alpha-helices. The alpha-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.
Department of Chemistry, Department of Biology, and Department of Biochemistry and Microbiology, Université Laval, Québec (Québec) G1K 7P4 Canada.
Thierry
T
Lefèvre
Jérémie
J
Leclerc
Jean-François
JF
Rioux-Dubé
Thierry
T
Buffeteau
Marie-Claude
MC
Paquin
Marie-Eve
ME
Rousseau
Isabelle
I
Cloutier
Michèle
M
Auger
Stéphane M
SM
Gagné
Simon
S
Boudreault
Conrad
C
Cloutier
Michel
M
Pézolet
D000818:Animals; D002942:Circular Dichroism; D019476:Insect Proteins / Q000737:chemistry*; D008853:Microscopy; D010455:Peptides / Q000032:analysis; D017433:Protein Structure, Secondary; D047011:Silk / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013112:Spiders / Q000378:metabolism*
D019476:Insect Proteins; D010455:Peptides; D047011:Silk; C011083:polyproline