title: Molecular engineering of avidin and hydrophobin for functional self-assembling interfaces.
abstract: Control over the functionality of interfaces through biomolecular engineering is a central tool for nanoscale technology as well as many current applications of biology. In this work we designed fusion proteins that combined the surface adhesion and interfacial activity of a hydrophobin-protein together with the high affinity biotin-binding capability of an avidin-protein. We found that an overall architecture that was based on a circularly permuted version of avidin, dual-chain avidin, and hydrophobin gave a highly functional combination. The protein was produced in the filamentous fungus Trichoderma reesei and was efficiently purified using an aqueous two-phase partitioning procedure. The surface adhesive properties were widely different compared to wild-type avidin. Functional characterization showed that the protein assembled on hydrophobic surfaces as a thin layer even at very low concentrations and efficiently bound a biotinylated compound. The work shows how the challenge of creating a fusion protein with proteins that form multimers can be solved by structural design and how protein self-assembly can be used to efficiently functionalize interfaces.
authors.affiliation: VTT Technical Research Institute of Finland, Tietotie 2, PO Box 1000, FI-02044 Espoo, Finland. Electronic address: katri.kurppa@vtt.fi.
authors.forename: Katri
authors.initials: K
authors.lastname: Kurppa
authors.affiliation: BioMediTech, University of Tampere and Tampere University Hospital, Biokatu 6, FI-33014 Tampere, Finland; Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland.
authors.forename: Vesa P
authors.initials: VP
authors.lastname: Hytönen
authors.affiliation: VTT Technical Research Institute of Finland, Tietotie 2, PO Box 1000, FI-02044 Espoo, Finland.
authors.forename: Tiina
authors.initials: T
authors.lastname: Nakari-Setälä
authors.affiliation: BioMediTech, University of Tampere and Tampere University Hospital, Biokatu 6, FI-33014 Tampere, Finland.
authors.forename: Markku S
authors.initials: MS
authors.lastname: Kulomaa
authors.affiliation: VTT Technical Research Institute of Finland, Tietotie 2, PO Box 1000, FI-02044 Espoo, Finland; Aalto University, Department of Biotechnology and Chemical Technology, Kemistintie 1, FI-00076 Espoo, Finland.
authors.forename: Markus B
authors.initials: MB
authors.lastname: Linder
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D000818:Animals; D001360:Avidin / Q000737:chemistry / Q000378:metabolism*; D015153:Blotting, Western; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D015202:Protein Engineering / Q000379:methods*; D058525:Quartz Crystal Microbalance Techniques; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D001360:Avidin
keywords: Avidin; Biofunctional surface; Hydrophobin; Nanomaterial; Protein engineering