The fibrous silk produced by bees, wasps, ants, or hornets is known to form a four-strand α-helical coiled coil superstructure. We have succeeded in showing the formation of this coiled coil structure not only in natural fibers, but also in artificial films made of regenerated silk of the hornet Vespa simillima xanthoptera using wide- and small-angle X-ray scatterings and polarized Fourier transform infrared spectroscopy. On the basis of time-resolved simultaneous synchrotron X-ray scattering observations for in situ monitoring of the structural changes in regenerated silk material during tensile deformation, we have shown that the application of tensile force under appropriate conditions induces a transition from the coiled α-helices to a cross-β-sheet superstructure. The four-stranded tertiary superstructure remains unchanged during this process. It has also been shown that the amorphous protein chains in the regenerated silk material are transformed into conventional β-sheet arrangements with varying orientation.

中文翻译：

---

螺旋状α-螺旋转变为交叉-β-片状上层结构

已知由蜜蜂，黄蜂，蚂蚁或黄蜂产生的纤维丝会形成四股α螺旋盘绕的线圈上层结构。我们已经成功地展示了这种盘绕线圈结构的形成，不仅在天然纤维中，而且在大黄蜂大黄蜂类黄an的再生丝制成的人造膜中，都使用了宽角度和小角度X射线散射以及偏振傅立叶变换红外光谱。基于时间分辨的同步加速器X射线散射观测值，用于原位监测拉伸变形过程中再生丝材料的结构变化，我们已经表明，在适当条件下施加拉力会导致从盘绕的α-转变螺旋交叉-β-片上层结构。在此过程中，四链三级上层建筑保持不变。还已经表明，再生丝材料中的无定形蛋白质链被转化为具有不同取向的常规β-折叠排列。