Fine discrimination of volatile compounds by graphene-immobilized odorant-binding proteins

• DOI: 10.1016/j.snb.2017.10.093
• Publication Date: 2017-10-18T15:00:18Z
• Authors: Caroline Kotlowski; Melanie Larisika; Patrick M. Guerin; Christoph Kleber; Thomas Kröber; Rosa Mastrogiacomo; Christoph Nowak; Paolo Pelosi; Stefan Schütz; Andreas Schwaighofer; Wolfgang Knoll
• Keywords: Wild type; Affinities; Binding affinities

We describe the fabrication and performance of a biosensor for odorants, using wildtype engineered mutants Italian honeybee (Apis mellifera ligustica) odorant binding protein 14 (OBP14), immobilized onto reduced graphene oxide field-effect transistor (rGO-FET). The properties when on are similar to those measured in solution, thus providing method measuring affinities small molecules as an alternative current fluorescence assay. Out chemicals tested, best ligands OBP14 were eugenol, homovanillic acid related compounds sharing phenol-methoxy backbone. Other chemicals, including methyl showed 100–1000 times lower. have also tested two OBP14. first, bearing HisTag at its N-terminus better orientation sensor surface, only minor differences compared wildtype. second contained additional disulfide bond between helices α3 α6, reducing dynamics leading higher affinity eugenol. These data demonstrate that it is feasible produce biosensors with desired ligand specificities by introducing selected mutations into structure OBPs or other active proteins.