PRODUCTION OF ADRENERGIC-RECEPTORS IN YEAST

Using a recombinant yeast strain expressing human beta(2) adrenergic r eceptors under a galactose-inducible promoter, we established conditio ns for receptor production in 1-15 liter fermenter culture, Crucial fa ctors contributing to consistent high-level expression included the us e of selective glucose-free medium, the maintenance of the pH of the c ulture at 7.2-7.5 and the presence of an antagonist. The expression st rategy and production conditions used with the beta(2) adrenergic rece ptor were then employed to express the human alpha(2)-C2 adrenergic re ceptor in Saccharomyces cerevisiae. Galactose-induced yeast cells disp layed specific, high-affinity [H-3]rauwolscine binding and contained a 50-kDa species recognized by an alpha(2)-C2 receptor specific antiser um. In fermenter culture, up to 10(5) high-affinity [H-3]rauwolscine b inding sites per cell (corresponding to 30-60 pmol/mg of protein) were obtained, The high expression level combined with relative ease and l ow cost of scaling-up make yeast a promising alternative to mammalian cells for the production of adrenergic and other G-protein-coupled rec eptors for structural studies.