title: Molecular nanosprings in spider capture-silk threads.
abstract: Spider capture silk is a natural material that outperforms almost any synthetic material in its combination of strength and elasticity. The structure of this remarkable material is still largely unknown, because spider-silk proteins have not been crystallized. Capture silk is the sticky spiral in the webs of orb-weaving spiders. Here we are investigating specifically the capture spiral threads from Araneus, an ecribellate orb-weaving spider. The major protein of these threads is flagelliform protein, a variety of silk fibroin. We present models for molecular and supramolecular structures of flagelliform protein, derived from amino acid sequences, force spectroscopy (molecular pulling) and stretching of bulk capture web. Pulling on molecules in capture-silk fibres from Araneus has revealed rupture peaks due to sacrificial bonds, characteristic of other self-healing biomaterials. The overall force changes are exponential for both capture-silk molecules and intact strands of capture silk.
authors.affiliation: Department of Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Becker
authors.forename: Emin
authors.initials: E
authors.lastname: Oroudjev
authors.forename: Stephanie
authors.initials: S
authors.lastname: Mutz
authors.forename: Jason P
authors.initials: JP
authors.lastname: Cleveland
authors.forename: Paul K
authors.initials: PK
authors.lastname: Hansma
authors.forename: Cheryl Y
authors.initials: CY
authors.lastname: Hayashi
authors.forename: Dmitrii E
authors.initials: DE
authors.lastname: Makarov
authors.forename: Helen G
authors.initials: HG
authors.lastname: Hansma
mesh_terms: D000818:Animals; D004548:Elasticity; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force / Q000379:methods*; D008958:Models, Molecular; D036103:Nanotechnology / Q000379:methods*; D011506:Proteins / Q000737:chemistry* / Q000502:physiology; D013112:Spiders / Q000737:chemistry* / Q000502:physiology; D013314:Stress, Mechanical
chemical_list: C404864:FLAG protein, Nephila; D046911:Macromolecular Substances; D011506:Proteins