title: Polyelectrolyte Fiber Assembly of Plant-Derived Spider Silk-like Proteins.
abstract: Spider dragline silk is a proteinaceous material that combines superior toughness and biocompatibility, which makes it a promising biomaterial. The distinct protein structure and the fiber formation process contribute to the superior toughness of dragline silk. Previously, we have produced recombinant spider silk-like proteins in transgenic tobacco that are readily purified from plant extracts. The plant-derived spidroin-like proteins consisted of native major ampullate spidroin 1 or spidroin 2 N- and C-termini flanking 8, 16, or 32 copies of their respective consensus block repeats (mini-spidroins). Here, we present the generation of fibers from mini-spidroins (rMaSp1R8 and rMaSp2R8) by polyelectrolyte complex formation using an anionic polyelectrolyte, gellan gum. Mini-spidroins, when treated with acetic acid and cross-linked by glutaraldehyde, formed a thin film at the interface when overlaid with a gellan gum solution. Immediate pulling of the film resulted in autofluorescent fibrous materials from either mini-spidroin alone or a combination of rMaSp1R8 and rMaSp2R8 (70:30). Addition of chitosan to the mini-spidroin solutions permitted continuous fiber production until the spinning dope supply was exhausted. When air-dried as-spun fibers were rehydrated and stretched in water, the fiber diameter decreased and the overall toughness improved. This study showed that spider silk-like fibers can be produced in large quantities through charge attraction that assembles chitosan, mini-spidroins, and gellan gum into fibrous complexes. We speculate that the spider silk self-assembly process in the duct may involve attraction of variously charged chitinous polymers, spidroins, and glycoproteins.
authors.affiliation: Department of Genetics and Biochemistry, Clemson University , 130 McGinty Court, Robert F. Poole Agricultural Center, Room 154, Clemson, South Carolina 29634, United States.
authors.forename: Congyue Annie
authors.initials: CA
authors.lastname: Peng
authors.affiliation: Department of Genetics and Biochemistry, Clemson University , 130 McGinty Court, Robert F. Poole Agricultural Center, Room 154, Clemson, South Carolina 29634, United States.
authors.forename: Julia
authors.initials: J
authors.lastname: Russo
authors.affiliation: Department of Genetics and Biochemistry, Clemson University , 130 McGinty Court, Robert F. Poole Agricultural Center, Room 154, Clemson, South Carolina 29634, United States.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Lyda
authors.affiliation: Department of Genetics and Biochemistry, Clemson University , 130 McGinty Court, Robert F. Poole Agricultural Center, Room 154, Clemson, South Carolina 29634, United States.
authors.forename: William R
authors.identifier: 0000-0003-4580-1939
authors.initials: WR
authors.lastname: Marcotte
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis; D048271:Chitosan / Q000737:chemistry; D005349:Fibroins / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D000071228:Polyelectrolytes / Q000138:chemical synthesis*; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013112:Spiders; D014026:Nicotiana / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D010940:Plant Proteins; D000071228:Polyelectrolytes; D011135:Polysaccharides, Bacterial; D011994:Recombinant Proteins; C086087:spidroin 1; C076815:spidroin 2; C048288:gellan gum; D005349:Fibroins; D048271:Chitosan