Interplay of Different Major Ampullate Spidroins during Assembly and Implications for Fiber Mechanics

• Published in: Advanced materials (Weinheim) 2021-03, Vol.33 (9), p.e2006499-n/a
• Main Authors: Saric, Merisa, Eisoldt, Lukas, Döring, Volker, Scheibel, Thomas
• Format: Article
• Language: English
• Subjects: Assembly; bioinspired fibers; Communication; Communications; Dimerization; Dopes; E coli; heterodimers; Mechanical properties; Mechanics (physics); protein interplay; self‐assembly; Silk; spider silk
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202006499

Major ampullate (MA) spider silk has fascinating mechanical properties combining strength and elasticity. All known natural MA silks contain at least two or more different spidroins; however, it is unknown why and if there is any interplay in the spinning dope. Here, two different spidroins from Araneus diadematus are co‐produced in Escherichia coli to study the possible dimerization and effects thereof on the mechanical properties of fibers. During the production of the two spidroins, a mixture of homo‐ and heterodimers is formed triggered by the carboxyl‐terminal domains. Interestingly, homodimeric species of the individual spidroins self‐assemble differently in comparison to heterodimers, and stoichiometric mixtures of homo‐ and heterodimers yield spidroin networks upon assembly with huge impact on fiber mechanics upon spinning. The obtained results provide the basis for man‐made tuning of spinning dopes to yield high‐performance fibers. Natural spider major ampullate silk exhibits mechanical properties unmatched by most other known natural or man‐made fibrous materials. Upon recombinant co‐production of two different spidroins derived from one spider species, they interconnect already in solution and during assembly. Their interplay yields fibers with overall properties different to those of one‐protein fibers, but equaling that of the natural blueprint.