Honeybee silk: recombinant protein production, assembly and fiber spinning

Transgenic production of silkworm and spider silks as biomaterials has posed intrinsic problems due to the large size and repetitive nature of the silk proteins. In contrast the silk of honeybees (Apis mellifera) is composed of a family of four small and non-repetitive fibrous proteins. We report recombinant production and purification of the four full-length unmodified honeybee silk proteins in Escherichia coli at substantial yields of 0.2-2.5 g/L. Under the correct conditions the recombinant proteins self-assembled to reproduce the native coiled coil structure. Using a simple biomimetic spinning system we could fabricate recombinant silk fibers that replicated the tensile strength of the native material.