Mechanism of silk processing in insects and spiders
Mechanism of silk processing in insects and spiders
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DOI：
10.1038/nature01809
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发表时间：
2003-08-28
期刊：
影响因子：
64.8
通讯作者：
Kaplan, DL
中科院分区：
文献类型：
--
作者：
Jin, HJ;Kaplan, DL
昆虫和蜘蛛吐丝会形成具有高强度和韧性的纤维（1）。由于对丝腺中蛋白质加工过程缺乏了解，阻碍了在体外从重组或基因工程蚕丝中重现这些特性。在此我们报道，从重组家蚕丝素蛋白水溶液中鉴定出乳液形成和胶束结构，这是控制水和蛋白质 - 蛋白质相互作用过程中的第一步。这些结构的大小（直径100 - 200纳米）可以根据丝蛋白一级序列的疏水性图谱来预测（2）。随着丝素蛋白浓度的增加，这些胶束随后聚集成更大的“小球”和凝胶状，同时由于蛋白质的亲水区散布在较大的疏水区之间而保持溶解性。经过物理剪切或拉伸结构转变后，双折射增加且形态排列有序，这表明该过程模拟了体内类似天然丝蛋白的行为。这些丝材料的最终形态特征与在天然家蚕纤维中观察到的相似。
Silk spinning by insects and spiders leads to the formation of fibres that exhibit high strength and toughness(1). The lack of understanding of the protein processing in silk glands has prevented the recapitulation of these properties in vitro from reconstituted or genetically engineered silks. Here we report the identification of emulsion formation and micellar structures from aqueous solutions of reconstituted silkworm silk fibroin as a first step in the process to control water and protein-protein interactions. The sizes (100-200 nm diameter) of these structures could be predicted from hydrophobicity plots of silk protein primary sequence(2). These micelles subsequently aggregated into larger 'globules' and gel-like states as the concentration of silk fibroin increased, while maintaining solubility owing to the hydrophilic regions of the protein interspersed among the larger hydrophobic regions. Upon physical shearing or stretching structural transitions, increased birefringence and morphological alignment were demonstrated, indicating that this process mimics the behaviour of similar native silk proteins in vivo. Final morphological features of these silk materials are similar to those observed in native silkworm fibres.