Liu Yi, Sponner Alexander, Porter David, Vollrath Fritz
Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom.
Biomacromolecules. 2008 Jan;9(1):116-21. doi: 10.1021/bm700877g. Epub 2007 Dec 4.
Major ampullate (MAA) silks from a variety of spider species were collected by artificial silking that adjusted the samples to have similar breaking strains. Those silks are highly comparable in post-yield mechanical properties, but their supercontraction behaviors and initial moduli vary in large ranges and both correlate with the content of one amino acid, proline. These relationships, in combination with protein sequence data, support the hypothesis that the proline-related motif, that is, GPGXX, may play a key role in silk. This also explains the interspecific variability of spider dragline silk. Moreover, MAA silks from three representative species were prepared in a range of processing conditions and their mechanical properties were compared. Our results indicate how chemical compositions, coupled with processing conditions, shape the mechanical properties of the spider silk.
通过人工缫丝收集了多种蜘蛛物种的大壶状腺（MAA）丝，调整样本使其具有相似的断裂应变。这些丝在屈服后力学性能上具有高度可比性，但它们的超收缩行为和初始模量在很大范围内变化，并且都与一种氨基酸脯氨酸的含量相关。这些关系与蛋白质序列数据相结合，支持了脯氨酸相关基序（即GPGXX）可能在丝中起关键作用的假设。这也解释了蜘蛛拖牵丝的种间变异性。此外，在一系列加工条件下制备了来自三种代表性物种的MAA丝，并比较了它们的力学性能。我们的结果表明化学成分与加工条件如何塑造蜘蛛丝的力学性能。
