By mimicking biological olfaction, biosensors have been used for the detection of important ligands in complex environments. An olfactory biosensor based on chemosensory proteins (CSPs) was designed by immobilizing honeybee CSPs (Ac-ASP3) on the interdigitated golden electrodes. Its responses to ligands of pheromones and floral odors were recorded by impedance spectroscopy. The relative decrease of charge transfer resistance of the biosensor is proportional to the logarithm of ligand concentration from 10(-7)M to 10(-3)M. To explore the molecular recognition processes of the biosensor, the tertiary structure of the protein was modeled and the protein-ligand interactions were investigated by the molecular docking. Our docking results verified the validity of experiments and showed that the specific ligands could form hydrogen bonds with some of the conserved residues, such as Cys 60 and Gln 64 of Ac-ASP3. Furthermore, combining the molecular modeling with impedance detection, the accuracy, specificity and predictability of the ligands binding to the protein could be improved. Thus, CSPs will provide a promising approach for chemical molecular sensing at low concentrations.
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