Yang Dong, Wang Suyang, Wang Kangkang, Zheng Shengwu, Zan Xingjie, Wen Rui
Department of Radiation and Medical Oncology, the Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province 325035, China.
School of Ophthalmology and Optometry, Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, Zhejiang Province 325035, China.
ACS Biomater Sci Eng. 2023 Dec 11;9(12):6670-6682. doi: 10.1021/acsbiomaterials.3c01194. Epub 2023 Nov 29.
Orb-weaving spiders can use an array of specialized silks with diverse mechanical properties and functions for daily survival. Of all spider silk types, aciniform silk is the toughest silk fiber that combines high strength and elasticity. Although aciniform spidroins (AcSp) are the main protein in aciniform silks, their complete genes have rarely been characterized until now. Moreover, the structural and physical properties of AcSp variant proteins within the species are also unclear. Here, we present three full-length AcSp genes (named , , and ) from the orb-weaving spider and investigate the structural and mechanical features of these three AcSp repetitive domains. We demonstrate that all three AcSp proteins have mainly α-helical structural features in neutral solution and high thermal stability. Significantly, the AcSp2 repetitive domain shows a pH-dependent structural transition from α to β conformations and can self-assemble into amyloid fibrils under acidic conditions, which is the first reported AcSp repetitive domain with pH-dependent self-assembly capacity. Compared with the other two AcSp spidroins, AcSp2 demonstrated the lowest expression level in the aciniform gland but had the highest strength for its silk fiber. Collectively, our findings provide new insight into the physical properties of each component of aciniform silk and expand the repertoire of known spidroin sequences for the synthesis of artificial silk materials.
圆蛛可以利用一系列具有不同机械性能和功能的特殊丝来维持日常生存。在所有蜘蛛丝类型中，aciniform丝是结合了高强度和高弹性的最坚韧的丝纤维。尽管aciniform蛛丝蛋白（AcSp）是aciniform丝中的主要蛋白质，但直到现在它们的完整基因仍很少被鉴定。此外，该物种内AcSp变体蛋白的结构和物理特性也不清楚。在这里，我们展示了来自圆蛛的三个全长AcSp基因（命名为 、 和 ），并研究了这三个AcSp重复结构域的结构和机械特征。我们证明，所有这三种AcSp蛋白在中性溶液中主要具有α-螺旋结构特征且具有高热稳定性。值得注意的是，AcSp2重复结构域显示出从α构象到β构象的pH依赖性结构转变，并且在酸性条件下可以自组装成淀粉样纤维，这是首次报道的具有pH依赖性自组装能力的AcSp重复结构域。与其他两种AcSp蛛丝蛋白相比，AcSp2在aciniform腺中的表达水平最低，但其丝纤维的强度最高。总的来说，我们的研究结果为aciniform丝各成分的物理性质提供了新的见解，并扩展了用于合成人造丝材料已知蛛丝蛋白序列的种类。
