论文标题：The transcriptome of Darwin’s bark spider silk glands predicts proteins contributing to dragline silk toughness

期刊：Communications Chemistry

作者：Jessica E. Garb,Robert A. Haney,Evelyn E. Schwager,Matja? Gregori?,Matja? Kuntner,Ingi Agnarsson,Todd A. Blackledge

发表时间：2019/07/25

数字识别码：10.1038/s42003-019-0496-1

本周《通讯-生物学》发表的一篇论文The transcriptome of Darwin’s bark spider silkglands predicts proteins contributing to draglinesilk toughness报道了一种或可以解释达尔文树皮蛛蛛丝的超凡韧性的新基因。这项发现或许对设计新型生物材料具有一定意义。

图1：达尔文树皮蛛(Caerostris darwini)使用蛛丝腺，以极长的蛛丝导管织出已知最大的圆网。

达尔文树皮蛛可以织出已知最大的圆网，蛛丝最长可达25米。达尔文树皮蛛用来构建蛛网结构轮廓的牵引丝是已知最强韧的生物材料，其韧性是Kevlar®合成纤维的10倍。但是，达尔文树皮蛛的蛛丝为何能拥有如此极致的韧性——用来衡量强度和可延展性的属性——仍是未知。

Jessica Garb及同事对达尔文树皮蛛丝腺内表达的基因做了测序，发现了一种不同寻常的蛛丝基因。虽然达尔文树皮蛛所生成的主要蛛丝蛋白和其他蜘蛛一样，但是它们还会生成一种具有一个独特重复序列的蛋白。该序列包含大量脯氨酸——一种已知可以使蛛丝更具有弹性的氨基酸。作者认为是这一独特的蛋白序列使达尔文树皮蛛的蛛丝变得如此强韧。

摘要：Darwin’s bark spider (Caerostris darwini) produces giant orb webs from dragline silk that can be twice as tough as other silks, making it the toughest biological material. This extreme toughness comes from increased extensibility relative to other draglines. We show C. darwinidragline-producing major ampullate (MA) glands highly express a novel silk gene transcript (MaSp4) encoding a protein that diverges markedly from closely related proteins and contains abundant proline, known to confer silk extensibility, in a unique GPGPQ amino acid motif. This suggests C. darwini evolved distinct proteins that may have increased its dragline’s toughness, enabling giant webs. Caerostris darwini’s MA spinning ducts also appear unusually long, potentially facilitating alignment of silk proteins into extremely tough fibers. Thus, a suite of novel traits from the level of genes to spinning physiology to silk biomechanics are associated with the unique ecology of Darwin’s bark spider, presenting innovative designs for engineering biomaterials.

（来源：科学网）