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Recombinant Spidroins Fully Replicate Primary Mechanical Properties of Natural Spider SilkDragline spider silk is among the strongest and toughest bio-based materials, capable of outperforming most synthetic polymers and even some metal alloys.1,2,3,4 These properties have gained spider silk a growing list of potential applications that, coupled with the impracticalities of spider farming, have driven a decades-long effort to produce recombinant spider silk proteins (spidroins) in engineered heterologous hosts.2 However, these efforts have so far been unable to yield synthetic silk fibers with mechanical properties equivalent to natural spider silk, largely due to an inability to stably produce highly repetitive, high molecular weight (MW) spidroins in heterologous hosts.1,5 Here we address these issues by combining synthetic biology techniques with split intein (SI)- mediated ligation for the bioproduction of spidroins with unprecedented MW (556 kDa), containing 192 repeat motifs of the Nephila clavipes MaSp1 dragline spidroin. Fibers spun from these synthetic spidroins display ultimate tensile strength (σ), modulus (E), extensibility (ε), and toughness (UT) of 1.03 +/- 0.11 GPa, 13.7 +/- 3.0 GPa, 18 +/- 6%, and 114 +/- 51 MJ/m3, respectively-equivalent to the performance of natural N. clavipes dragline silk.6 This work demonstrates for the first time that microbially produced synthetic silk fibers can match the performance of natural silk fibers by all common metrics (σ, E, ε, UT), providing a more dependable source of high-strength fibers to replace natural spider silks for mechanically demanding applications. Furthermore, our biosynthetic platform can be potentially expanded for the assembly and production of other protein-based materials with high MW and repetitive sequences that have so far been impossible to synthesize by genetic means alone.
Document ID
20180007385
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Bowen, Christopher H. (Washington Univ. Saint Louis, MO, United States)
Dai, Bin (Washington Univ. Saint Louis, MO, United States)
Sargent, Cameron (Washington Univ. Saint Louis, MO, United States)
Bai, Wenqin (Washington Univ. Saint Louis, MO, United States)
Ladiwala, Pranay (Washington Univ. Saint Louis, MO, United States)
Feng, Huibao (Washington Univ. Saint Louis, MO, United States)
Huang, Wenwen
Kaplan, David
Galazka, Jonathan (NASA Ames Research Center Moffett Field, CA, United States)
Zhang, Fuzhong (Washington Univ. Saint Louis, MO, United States)
Date Acquired
November 1, 2018
Publication Date
January 1, 2018
Publication Information
Publisher: American Chemical Soceity
Subject Category
Life Sciences (General)
Report/Patent Number
ARC-E-DAA-TN58692
Report Number: ARC-E-DAA-TN58692
Funding Number(s)
CONTRACT_GRANT: NNX15AU45G
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
spider silk
split-intein
synthetic biology

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