The slime of velvet worms (Onychophora) is a protein-based bioadhesive that undergoes rapid, yet reversible transition from a fluid into stiff fibers used for prey capture and defense, but the mechanism by which this phase transition functions is largely unknown. Here, integrating transcriptomic and proteomic approaches with AI-guided structure predictions, we discover a group of evolutionarily conserved leucine-rich repeat (LRR) proteins in velvet worm slime that readily adopt a receptor-like, protein-binding “horseshoe” structure. Our structural predictions suggest dimerization of LRR proteins and support their interactions with conserved β-sheet-rich domains of high-molecular-weight proteins, the primary building blocks of velvet worm slime fibers. This suggests that LRR proteins might be involved in reversible, receptor-based supramolecular interactions in these biofibers, providing potential avenues for fabricating fully recyclable (bio)polymeric materials.

中文翻译：

---

天鹅绒蠕虫的粘附弹状粘液中保守的富含亮氨酸的重复蛋白


天鹅绒蠕虫的粘液 （Onychophora） 是一种基于蛋白质的生物粘附物，它从液体快速但可逆地转变为用于捕获和防御猎物的坚硬纤维，但这种相变发挥作用的机制在很大程度上是未知的。在这里，将转录组学和蛋白质组学方法与 AI 引导的结构预测相结合，我们在天鹅绒蠕虫粘液中发现了一组进化上保守的富含亮氨酸的重复序列 （LRR） 蛋白，它们很容易采用受体样、蛋白质结合的“马蹄”结构。我们的结构预测表明 LRR 蛋白的二聚化，并支持它们与高分子量蛋白的保守β片富集结构域的相互作用，这些结构域是天鹅绒蠕虫粘液纤维的主要组成部分。这表明 LRR 蛋白可能参与这些生物纤维中可逆的、基于受体的超分子相互作用，为制造完全可回收的 （生物） 聚合物材料提供了潜在的途径。