The N-terminal replacement of an olfactory receptor for the development of a yeast-based biomimetic odor sensor.

For the development of a biomimetic odor-sensing system, we investigated the effects of replacing the N-terminus of an olfactory receptor (OR) on its functional expression in the budding yeast, Saccharomyces cerevisiae. Using the mouse olfactory receptor OR226 (mOR226), three types of chimeric ORs were constructed by replacing N-terminal regions of mOR226 with the corresponding regions of the rat I7 receptor, which is known to be functionally expressed in yeast. The replacement of the N-terminal region of mOR226 dramatically affected the expression and localization of the receptor and improved the sensing ability of the yeast cells for the odorant. Furthermore, the replacement of the endogenous yeast G-protein α subunit (Gpa1) by the OR-specific G(olf) drastically elevated the odorant-sensing ability of the yeast cells and caused the cells to display a dose-dependent responsiveness to the odorant. Because of the suitability of yeast cells for screening large-scale libraries, the strategy presented here would be useful for the establishment of advanced biomimetic odor-sensing systems.