Heterologous Expression of Pseudomonas putida Methyl-Accepting Chemotaxis Proteins Yields Escherichia coli Cells Chemotactic to Aromatic Compounds.

, commonly used in chemotaxis studies, is attracted mostly by amino acids, sugars, and peptides. We envisioned modifying the chemotaxis specificity of by expressing heterologous chemoreceptors from enabling attraction either to toluene or benzoate. The gene encoding the type 40-helical bundle (40H) methyl-accepting chemoreceptor for toluene from MT53 and the gene for the type 40H receptor for benzoate and related molecules from F1 were expressed from the promoter on a plasmid in motile wild-type MG1655. cells expressing McpT accumulated in chemoattraction assays to sources with 60 to 200 μM toluene, although less strongly than the response to 100 μM serine, but statistically significantly stronger than that to sources without any added attractant. An McpT-mCherry fusion protein was detectably expressed in and yielded weak but distinguishable membranes and polar foci in 1% of cells. cells expressing PcaY showed weak attraction to 0.1 to 1 mM benzoate, but 50 to 70% of cells localized the PcaY-mCherry fusion to their membrane. We conclude that implementing heterologous receptors in the chemotaxis network is possible and, upon improvement of the compatibility of the type 40H chemoreceptors, may bear interest for biosensing. Bacterial chemotaxis might be harnessed for the development of rapid biosensors, in which chemical availability is deduced from cell accumulation to chemoattractants over time. Chemotaxis of has been well studied, but the bacterium is not attracted to chemicals of environmental concern, such as aromatic solvents. We show here that heterologous chemoreceptors for aromatic compounds from at least partly functionally complement the chemotaxis network, yielding cells attracted to toluene or benzoate. Complementation was still inferior to native chemoattractants, like serine, but our study demonstrates the potential for obtaining selective sensing for aromatic compounds in .