Production and Properties of Triple Chimeric Spidroins.

All spider silk proteins (spidroins) are composed of N- and C-terminal domains (NT and CT) that act as regulators of silk solubility and assembly and a central repetitive region, which confers mechanical properties to the fiber. Among the seven types of spider silks, aciniform silk has the highest toughness. Herein, we fused NT and CT domains from major and minor ampullate spidroins (MaSps and MiSps), respectively, to 1-4 repeat domains (W) from another type of spidroin, aciniform spidroin 1(AcSp1). Although the three domains originate from distantly related spidroin types, they keep their respective characteristics in the chimeric spidroins. Furthermore, all chimeric spidroins could form silk-like fibers by manual-drawing. In contrast to fibers made in the same manner from W domains only, NTWCT fibers show superior mechanical properties. Our results suggest that chimeric spidroins with NT, CT, and repeat domains can be designed to form fibers with various mechanical properties.