Engineering enzymatically active spider silk materials from high-yield expression to IgG-cleaving hydrogels and fibers

Abstract The development of bioactive protein-based materials hinges on scalable expression systems and robust and mild processing methods. Here we report the successful bacterial overexpression and purification of a fusion protein comprising the mini-spidroin (A 3 I) 3 -A 14 and the Immunoglobulin G (IgG)-degrading enzyme IdeS. High-density fed-batch bioreactor cultivation resulted in expression levels of 7.2 g/L, demonstrating the scalability of the system. Structural and functional characterization confirmed that the IdeS moeity was folded and retained enzymatic activity. Importantly, the high solubility of the fusion protein ( > 200 mg/mL), combined with the mini-spidroin’s ability to assemble into gels and fibers, allowed us to develop self-assembled hydrogels and wet-spun fibers that maintained enzymatic function. Notably, enzymatic activity was preserved in fibers stored for prolonged times under both wet and dry conditions. These findings illustrate the potential of spidroin fusion proteins as a modular platform for producing robust bioactive materials in a scalable process, offering new avenues for biomedical applications.