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Spider silks are protein-based “biopolymer” filaments or threads secreted by specialized epithelial cells as concentrated soluble precursors of highly repetitive primary sequences. Spider dragline silk is a flexible, lightweight fiber of extraordinary strength and toughness comparable to that of synthetic high-performance fibers. We sought to “biomimic” the process of spider silk production by expressing in mammalian cells the dragline silk genes (ADF-3/MaSpII and MaSpI) of two spider species. We produced soluble recombinant (rc)-dragline silk proteins with molecular masses of 60 to 140 kilodaltons. We demonstrated the wet spinning of silk monofilaments spun from a concentrated aqueous solution of soluble rc-spider silk protein (ADF-3; 60 kilodaltons) under modest shear and coagulation conditions. The spun fibers were water insoluble with a fine diameter (10 to 40 micrometers) and exhibited toughness and modulus values comparable to those of native dragline silks but with lower tenacity. Dope solutions with rc-silk protein concentrations >20% and postspinning draw were necessary to achieve improved mechanical properties of the spun fibers. Fiber properties correlated with finer fiber diameter and increased birefringence. [ABSTRACT FROM AUTHOR]

The article provides information pertaining to the silk of the orb web spiders. Araneoid and deinopoid orb weavers are the two lineages of orb weaving that use identical behavioral sequences and spinning apparatuses to develop webs. Spiders silks are composed of protiens combined in an abdominal gland, this gland has three types which produce the fibers that is used in orb-web construction, the major ampullates for frame and radial fibers, minor ampullates for temporary spiral scaffolding and flagelliforms for capture spiral axial fibers.