Expression And Characterization Of Chimeric Spidroins Fromflagelliform-Aciniform Repetitive Modules

Spiders can produce up to seven different types of silks or glues with different mechanical properties. Of these, flagelliform (Flag) silk is the most elastic, and aciniform (AcSp1) silk is the toughest. To produce a chimeric spider silk (spidroin) Flag(R)-AcSp1(R), we fused one repetitive module of flagelliform silk fromAraneus ventricosusand one repetitive module of aciniform silk fromArgiope trifasciata. The recombinant protein expressed inE. coliformed silk-like fibers by manual-drawing. CD analysis showed that the secondary structure of Flag(R)-AcSp1(R)spidroin remained stable during the gradual reduction of pH from 7.0 to 5.5. The spectrum of FTIR indicated that the secondary structure of Flag(R)-AcSp1(R)changed from alpha-helix to beta-sheet. The conformation change of Flag(R)-AcSp1(R)was similar to other spidroins in the fiber formation process. SEM analysis revealed that the mean diameter of the fibers was around 1 similar to 2 mu m, and the surface was smooth and uniform. The chimeric fibers exhibited superior toughness (similar to 33.1 MJ/m(3)) and tensile strength (similar to 261.4 MPa). This study provides new insight into design of chimeric spider silks with high mechanical properties.