title: Efficient purification of recombinant proteins using hydrophobins as tags in surfactant-based two-phase systems.
abstract: In this work we describe the new concept of using fungal hydrophobins as efficient tags for purification of recombinant fusion proteins by aqueous two-phase separation. Hydrophobins are a group of small surface-active proteins produced by filamentous fungi. Some characteristics of hydrophobins are that they are relatively small (approximately 100 amino acids), they contain eight disulfide-forming Cys residues in a conserved pattern, and they self-assemble on interfaces. The aqueous two-phase systems studied were based on nonionic surfactants that phase-separate at certain temperatures. We show that the use of hydrophobins as tags has many advantages such as high selectivity and good yield and is technically very simple to perform. Fusion proteins with target proteins of different molecular size were compared to the corresponding free proteins using a set of different surfactants. This gave an understanding on which factors influence the separation and what rationale should be used for optimization. This unusually strong and specific interaction between polymeric surfactants and a soluble protein shows promise for new developments in interfacing proteins and nonbiological materials for other applications as well.
authors.affiliation: VTT Biotechnology, Technical Research Centre of Finland, P.O. Box 1500, FIN-02044 VTT, Finland. markus.linder@vtt.fi
authors.forename: Markus B
authors.initials: MB
authors.lastname: Linder
authors.forename: Mingqiang
authors.initials: M
authors.lastname: Qiao
authors.forename: Frank
authors.initials: F
authors.lastname: Laumen
authors.forename: Klaus
authors.initials: K
authors.lastname: Selber
authors.forename: Teppo
authors.initials: T
authors.lastname: Hyytiä
authors.forename: Tiina
authors.initials: T
authors.lastname: Nakari-Setälä
authors.forename: Merja E
authors.initials: ME
authors.lastname: Penttilä
mesh_terms: D001681:Biological Assay / Q000379:methods; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D007202:Indicators and Reagents / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification*; D013501:Surface-Active Agents / Q000378:metabolism*; D014242:Trichoderma / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D007202:Indicators and Reagents; D011993:Recombinant Fusion Proteins; D013501:Surface-Active Agents