3LR8

Self-assembly of spider silk proteins is controlled by a pH-sensitive relay

3LR8 の概要

• エントリーDOI: 10.2210/pdb3lr8/pdb
• 関連するPDBエントリー: 3LR2 3LR6 3LRD
• 分子名称: Major ampullate spidroin 1, 1,2-ETHANEDIOL, DI(HYDROXYETHYL)ETHER, ... (5 entities in total)
• 機能のキーワード: dragline spider silk, self-assembly, ph-dependence, nt e79q mutant, structural protein
• 由来する生物種: Euprosthenops australis
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 29126.31

構造登録者

Askarieh, G.,Hedhammar, H.,Nordling, K.,Rising, A.,Johansson, J.,Knight, S.D. (登録日: 2010-02-10, 公開日: 2010-05-12, 最終更新日: 2024-04-03)

主引用文献

Askarieh, G.,Hedhammar, M.,Nordling, K.,Saenz, A.,Casals, C.,Rising, A.,Johansson, J.,Knight, S.D.
Self-assembly of spider silk proteins is controlled by a pH-sensitive relay.
Nature, 465:236-238, 2010

PubMed Abstract: Nature's high-performance polymer, spider silk, consists of specific proteins, spidroins, with repetitive segments flanked by conserved non-repetitive domains. Spidroins are stored as a highly concentrated fluid dope. On silk formation, intermolecular interactions between repeat regions are established that provide strength and elasticity. How spiders manage to avoid premature spidroin aggregation before self-assembly is not yet established. A pH drop to 6.3 along the spider's spinning apparatus, altered salt composition and shear forces are believed to trigger the conversion to solid silk, but no molecular details are known. Miniature spidroins consisting of a few repetitive spidroin segments capped by the carboxy-terminal domain form metre-long silk-like fibres irrespective of pH. We discovered that incorporation of the amino-terminal domain of major ampullate spidroin 1 from the dragline of the nursery web spider Euprosthenops australis (NT) into mini-spidroins enables immediate, charge-dependent self-assembly at pH values around 6.3, but delays aggregation above pH 7. The X-ray structure of NT, determined to 1.7 A resolution, shows a homodimer of dipolar, antiparallel five-helix bundle subunits that lack homologues. The overall dimeric structure and observed charge distribution of NT is expected to be conserved through spider evolution and in all types of spidroins. Our results indicate a relay-like mechanism through which the N-terminal domain regulates spidroin assembly by inhibiting precocious aggregation during storage, and accelerating and directing self-assembly as the pH is lowered along the spider's silk extrusion duct.

PubMed: 20463740
DOI: 10.1038/nature08962

実験手法

X-RAY DIFFRACTION (2.3 Å)