Molecular nanosprings in spider capture-silk threads.
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.
Becker
Nathan
N
Department of Physics, University of California, Santa Barbara, California 93106, USA.
Oroudjev
Emin
E
Mutz
Stephanie
S
Cleveland
Jason P
JP
Hansma
Paul K
PK
Hayashi
Cheryl Y
CY
Makarov
Dmitrii E
DE
Hansma
Helen G
HG
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
C404864:FLAG protein, Nephila; D046911:Macromolecular Substances; D011506:Proteins