Solid state (13)C NMR and FT-IR spectroscopy of the cocoon silk of two common spiders.
The structure of the silk from cocoons of two common spiders, Araneus diadematus (family Araneidae) and Achaearanea tepidariorum (family Theridiidae) was investigated by means of (13)C solid state NMR and FT-IR spectroscopies. The combined use of these two techniques allowed us to highlight differences in the two samples. The cocoon silk of Achaearanea tepidariorum is essentially constituted by helical and beta-sheet structures, whereas that of Araneus diadematus shows a more complex structure, containing also beta-strands and beta-turns. Moreover, the former silk is essentially crystalline while the latter contains more mobile domains. The structural differences of the two cocoon silks are ascribed to the different habitat of the two species.
Bramanti
Emilia
E
Istituto per i Processi Chimico-Fisici, CNR, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy.
Catalano
Donata
D
Forte
Claudia
C
Giovanneschi
Mario
M
Masetti
Massimo
M
Veracini
Carlo Alberto
CA
D000818:Animals; D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011487:Protein Conformation; D047011:Silk / Q000737:chemistry*; D013045:Species Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013112:Spiders
D002247:Carbon Isotopes; D047011:Silk