title: Recombinant spider silk genetically functionalized with affinity domains.
abstract: Functionalization of biocompatible materials for presentation of active protein domains is an area of growing interest. Herein, we describe a strategy for functionalization of recombinant spider silk via gene fusion to affinity domains of broad biotechnological use. Four affinity domains of different origin and structure; the IgG-binding domains Z and C2, the albumin-binding domain ABD, and the biotin-binding domain M4, were all successfully produced as soluble silk fusion proteins under nondenaturing purification conditions. Silk films and fibers produced from the fusion proteins were demonstrated to be chemically and thermally stable. Still, the bioactive domains are concluded to be folded and accessible, since their respective targets could be selectively captured from complex samples, including rabbit serum and human plasma. Interestingly, materials produced from mixtures of two different silk fusion proteins displayed combined binding properties, suggesting that tailor-made materials with desired stoichiometry and surface distributions of several binding domains can be produced. Further, use of the IgG binding ability as a general mean for presentation of desired biomolecules could be demonstrated for a human vascular endothelial growth factor (hVEGF) model system, via a first capture of anti-VEGF IgG to silk containing the Z-domain, followed by incubation with hVEGF. Taken together, this study demonstrates the potential of recombinant silk, genetically functionalized with affinity domains, for construction of biomaterials capable of presentation of almost any desired biomolecule.
authors.affiliation: Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences , Biomedical Center, SE-751 23 Uppsala, Sweden.
authors.forename: Ronnie
authors.initials: R
authors.lastname: Jansson
authors.forename: Naresh
authors.initials: N
authors.lastname: Thatikonda
authors.forename: Diana
authors.initials: D
authors.lastname: Lindberg
authors.forename: Anna
authors.initials: A
authors.lastname: Rising
authors.forename: Jan
authors.initials: J
authors.lastname: Johansson
authors.forename: Per-Åke
authors.initials: PÅ
authors.lastname: Nygren
authors.forename: My
authors.initials: M
authors.lastname: Hedhammar
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D047011:Silk / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013112:Spiders / Q000737:chemistry; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; D047011:Silk; D042461:Vascular Endothelial Growth Factor A