Spider silk is made of fibers whose mechanical properties exceed those of steel once the smaller density of spider silk is taken into account: A spider silk fiber spun around the earth’s equator would weigh not more than 500 g.
Harald Schwalbe and co-authors, Johann Wolfgang Goethe-University, Frankfurt, Germany, highlight current research into this remarkable material.
Formed of a polypeptide chain of an AQ repeat sequence, the silk has twelve AQ sequences that are flanked by non-repetitive N- and C-terminal domains. The authors look at how the two non-repeat domains – recently solved by NMR spectroscopy – form a dimeric, highly symmetric structure. This structure ensures the solubility of the protein when stored in the spider’s lumen and contributes to the other remarkable properties of spider silk.