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

Caroline Kotlowski, Melanie Larisika, Patrick Guerin, Christoph Kleber, Thomas Kröber, Rosa Mastrogiacomo, Christoph Nowak, Stefan Schütz, Andreas Schwaighofer, Wolfgang Knoll, Paolo Pelosi

    Research output: Contribution to journalArticlepeer-review


    We describe the fabrication and performance of a biosensor for odorants, using wildtype and engineered mutants of the Italian honeybee (Apis mellifera ligustica) odorant binding protein 14 (OBP14), immobilized onto a reduced graphene oxide field-effect transistor (rGO-FET). The binding properties of the protein when immobilized on the biosensor are similar to those measured in solution, thus providing a method for measuring affinities to small molecules as an alternative to the current fluorescence assay. Out of the 14 chemicals tested, the best ligands for wildtype OBP14 were eugenol, homovanillic acid and related compounds sharing a phenol-methoxy backbone. Other chemicals, including methyl eugenol, showed affinities to OBP14 100-1000 times lower. We have also tested two mutants of OBP14. The first, bearing a HisTag at its N-terminus for better orientation on the sensor surface, showed only minor differences in its binding properties for chemicals when compared to the wildtype. The second contained an additional disulfide bond between helices α3 and α6, thus reducing the dynamics of OBP14 and leading to a higher affinity for eugenol. These data also demonstrate that it is feasible to produce biosensors with desired ligand specificities by introducing selected mutations into the structure of OBPs or other active proteins.
    Original languageEnglish
    Pages (from-to)564-572
    Number of pages9
    JournalSensors and Actuators B-Chemical
    Publication statusPublished - 2018

    Research Field

    • Biosensor Technologies


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