MECHANISTIC UNDERSTANDING OF SPIDER SILK FORMATION BY SPIDROIN REPETITIVE DOMAINS

Abstract

Spider silk fibres reveal extraordinary physical properties. Besides, they are antimicrobial, hypoallergenic and biodegradable, therefore they have been widely used in biomedical applications recently. However, the mechanism of spider silk protein assembly into fibers is still unclear. Spider silk proteins consist of two non-repetitive terminal domains and hundreds of repetitive domains. Although one spider can produce seven types of silk proteins, only few repetitive domains can form silk fibre without the terminal domains. MiRP and AcRP from Triconephila antipodiana are two of them. In this study, recombinant MiRP and AcRP were investigated to understand their conformational change from -helical to -structured fibrils by focusing on their structure-function relationship. It was found the inter-helical ion-dipole interaction is maintaining a delicate balance between precipitation and fibril assembly. This information not only gets insight into the sophisticated spider silk formation process but also inspires studies on conformational conversions in other types of proteins.