Structural disorder in silk proteins reveals the emergence of elastomericity

Research output: Contribution to journalArticle

Abstract

Spider silks combine basic amino acids into strong and versatile fibers where the quality of the elastomer is attributed to the interaction of highly adapted protein motifs with a complex spinning process. The evaluation, however, of the interaction has remained elusive. Here, we present a novel analysis to study silk formation by examining the secondary structures of silk proteins in solution. Using the seven different silks of Nephila edulis as a benchmark system, we define a structural disorder parameter (the folding index, γ). We found that γ is highly correlated with the ratio of glycine present. Testing the correlation between glycine content and the folding index (γ) against a selected range of silks, we find quantitatively that, in order to achieve specialization with changes in mechanical performance, the spider's silks require higher structural flexibility at the expense of reduced stability and consequently an increased conversion-energy cost. Taken together, our biophysical and evolutionary findings reveal that silk elastomericity evolved in tandem with specializations in the process of silk spinning.

Details

Authors
  • Cedric Dicko
  • David Porter
  • Jason Bond
  • John M. Kenney
  • Fritz Vollrath
External organisations
  • University of Oxford
  • East Carolina University
Original languageEnglish
Pages (from-to)216-221
Number of pages6
JournalBiomacromolecules
Volume9
Issue number1
Publication statusPublished - 2008 Jan 1
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes