2mu3

Publication Abstract from PubMed

Spiders store spidroins in their silk glands as high concentration aqueous solutions, spinning these dopes into fibres with outstanding mechanical properties. Aciniform (or wrapping) silk is the toughest spider silk and is devoid of the short amino acid sequence motifs characteristic of the other spidroins. Using solution-state NMR spectroscopy, we demonstrate that the 200 amino acid Argiope trifasciata AcSp1 repeat unit contrasts with previously characterized spidroins, adopting a globular 5-helix bundle flanked by intrinsically disordered N- and C-terminal tails. Split-intein-mediated segmental NMR-active isotope-enrichment allowed unambiguous demonstration of modular and malleable "beads-on-a-string" concatemeric behaviour. Concatemers form fibres upon manual drawing with silk-like morphology and mechanical properties, alongside secondary structuring and orientation consistent with native AcSp1 fibres. AcSp1 structural stability varies locally, with the fifth helix denaturing most readily. The structural transition of aciniform spidroin from a mostly alpha-helical dope to a mixed alpha-helix/beta-sheet-containing fibre can be directly related to spidroin architecture and stability.

Spider wrapping silk fibre architecture arising from its modular soluble protein precursor.,Tremblay ML, Xu L, Lefevre T, Sarker M, Orrell KE, Leclerc J, Meng Q, Pezolet M, Auger M, Liu XQ, Rainey JK Sci Rep. 2015 Jun 26;5:11502. doi: 10.1038/srep11502. PMID:26112753^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.