May 13 2010
Five times the tensile strength of steel and triple that of the currently best synthetic fibers: Spider silk is a fascinating material. But no one has thus far succeeded in producing the super fibers synthetically.
How do spiders form long, highly stable and elastic fibers from the spider silk proteins stored in the silk gland within split seconds? Scientists from the Technische Universitaet Muenchen (TUM) and the University of Bayreuth have now succeeded in unraveling the secret. They present their results in the current issue of the prestigious scientific journal Nature.
“即使是由纯蜘蛛丝蛋白产生的纤维，自然蜘蛛丝的高弹性和极端拉伸强度也是无与伦比的，” Tu Muenchen高级研究所的Carl-Von-Linde教授Horst Kessler教授说。这突出了稳定的蜘蛛丝纤维的人工生产中的一个关键问题：蜘蛛如何设法保持丝绸腺中高浓度的原材料，随时准备产生高拉伸强度纤维。托马斯·舍贝尔（Thomas Scheibel）多年来一直在追求蜘蛛丝的秘密，直到2007年在TUM，此后在拜罗伊特大学（University of Bayreuth）。
Spider silk consists of protein molecules, long chains comprising thousands of amino-acid elements. X-ray structure analyses show that the finished fiber has areas in which several protein chains are interlinked via stable physical connections. These connections provide the high stability. Between these connections are unlinked areas that give the fibers their great elasticity.
The situation within the silk gland is, however, very different: The silk proteins are stored in high concentrations in an aqueous environment, awaiting deployment. The areas responsible for interlinking may not approach each other too closely; otherwise the proteins would clump up instantaneously. Hence, these molecules must have some kind of special storage configuration.
X-ray structure analysis, which is so successful in other domains, was of little help here, since it can only be used to analyze crystals. And up to the instant in which the solid silk fiber is formed, everything takes place in solution. The method of choice was therefore nuclear magnetic resonance spectroscopy (NMR). Using the equipment of the Bavarian NMR Center, Franz Hagn, a biochemist from Horst Kessler's work group at the Institute for Advanced Study (TUM-IAS) at the TU Muenchen, managed to unravel the structure of a control element responsible for the formation of the solid fiber. Now the researchers could, together with Lukas Eisoldt and John Hardy from Thomas Scheibel's group, shed light on this control element's mode of operation.
托马斯·舍贝尔（Thomas Scheibel）解释说：“在丝绸腺的存储条件下，这些控制域的配对连接在一起，使这两个链的相互链接区域都不能彼此平行。”“因此，有效地阻止了互连。”蛋白质链在外部和内部链的疏水部分中存储，并确保在水性环境中良好的溶解度。
当受保护的蛋白质进入纺丝管道时，它们会遇到一个完全不同的盐浓度和成分的环境。这使控制域的两个盐桥不稳定，链条可以展开。此外，狭窄的旋转管中的流动导致剪切力。长蛋白链并行对齐，从而将负责并排相互联系的区域放置。稳定的蜘蛛丝纤维形成。
"Our results have shown that the molecular switch we discovered at the C-terminal end of the protein chain is decisive, both for safe storage and for the fiber formation process," says Franz Hagn. An important foundation for these results was established through cooperation of Thomas Scheibel's group with Professor Andreas Bausch's workgroup at the Physics Department at TUM. Using microsystem technology, they developed an artificial spinning duct. Meanwhile the Bayreuth scientists are working intensively to develop a biomimetic spinning apparatus, within the framework of a federally supported joint project with industrial partners. The potential applications are countless, from resorbable surgical suture material to technical fibers for the automotive industry.
巴伐利亚NMR中心通过提供测试和测量时间来支持这项研究，德意志Forschungsgemeinschaft（DFG）（DFG），卓越综合蛋白质科学中心（CIPSM）和在Tu Muenchen，Tu Muenchen的高级研究所的卓越集群中心欧洲杯线上买球霍斯特·凯斯勒（Horst Kessler）自从成为荣誉以来就一直担任高级研究员。弗朗兹·哈格（Franz Hagn）的作品是由亚历山大·冯·洪堡基金会（Alexander von Humboldt Foundation）的拜耳列赛（Bayerisches Elitenetzwerk）的拜丽莎斯（Bayerisches Elitenetzwerk）巨头约翰·哈迪（John G. Hardy）资助的。
Source:http://portal.mytum.de/welcome