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Abstract

Spider silk is considered a promising next-generation biomaterial due to its exceptional toughness, coupled with its renewability and biodegradability. Contrary to the conventional view that spider silk is mainly composed of two types of silk proteins (spidroins), MaSp1 and MaSp2, multi-omics strategies are increasingly revealing that the inclusion of complex components confers the higher mechanical properties to the material. In this review, we focus on several recent findings that report essential components and mechanisms that are necessary to reproduce the properties of natural spider silk. First, we discuss the discovery of MaSp3, a newly identified spidroin that is a major component in the composition of spider silk, in addition to the previously understood MaSp1 and MaSp2. Moreover, the role of the Spider-silk Constituting Element (SpiCE), which is present in trace amounts but has been found to significantly increase the tensile strength of artificial spider silk, is explored. We also delve into the process of spidroin fibril formation through liquid-liquid phase separation (LLPS) that forms the hierarchical structure of spider silk. In addition, we review the correlation between amino acid sequences and mechanical properties such as toughness and supercontraction, as revealed by an analysis of 1,000 spiders. In conclusion, these recent findings contribute to the comprehensive understanding of the mechanisms that give spider silk its high mechanical properties and help to improve artificial spider silk production.