Lattice deformation and thermal stability of crystals in spider silk

Hwo Shuenn Sheu, Khin Win Phyu, Yuch Cheng Jean, Yung Ping Chiang, I. Min Tso, Hsuan Chen Wu, Jen Chang Yang, Shyue Lih Ferng

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The X-ray diffraction of dragline silks, produced by Nephila and Cyrtophora spiders, were measured by synchrotron radiation in their original states or in situ during stretching and heating. Nephila pilipes spiders construct a two-dimensional orb web that must be rebuilt in one or 2 days, but Cyrtophora spiders form a three-dimensional tent web that can exist for several weeks in a tropical forest. Diffraction patterns of N. pilipes and Cyrtophora draglines resemble each other. Crystals of two kinds are identified in these draglines; one is aligned parallel to the silk direction and another is less oriented. The less oriented crystal in Cyrtophora dragline is aligned better than that in N. pilipes dragline, which generates about three times stronger diffract intensity. Crystals in N. pilipes and C. moluccensis dragline silks have remarkable thermal stability. Equatorial reflections remain undiminished until 350 and 450°C for N. pilipes and C. moluccensis, respectively. In contrast, the meridional reflections S and (0 0 2), which are parallel to the silk thread, disappear at a temperature less than 100°C for C. moluccensis but remain for Nephila up to 100°C. Meridional reflections S and (0 0 2) shift to a smaller angle during stretching, whereas equatorial reflections remain constant in a range 1.0-1.3 times the original length. The position of the S reflection shifts rapidly in the first 10% of elongation from the original length but remains constant during subsequent stretching, whereas the (0 0 2) reflection shifts rapidly during the first 5% elongation from the original length and continues to shift subsequently. In contrast, the features of N. pilipes dragline alter insignificantly during stretching. Examination of the composition of amino acids of the draglines of N. pilipes and C. moluccensis indicates that a dragline of N. pilipes contains more glycine, but much less alanine, than that of C. moluccensis.

Original languageEnglish
Pages (from-to)267-273
Number of pages7
JournalInternational Journal of Biological Macromolecules
Volume34
Issue number5
DOIs
Publication statusPublished - Oct 2004
Externally publishedYes

Keywords

  • Lattice deformation
  • Spider silk
  • Thermostability
  • X-ray diffraction

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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