Engineering of Saccharomyces cerevisiae for sensing sweetness

With the rapidly increasing demand for sweeteners, it is necessary to establish an effective sweetness evaluation system for exploring new sweeteners. In this study, a gene circuit was constructed to couple with the inherent mitogen-activated protein kinase (MAPK) pathway in Saccharomyces cerevisiae to sense sweeteners. The Sst2, Far1, and Ste2 genes were knocked out to amplify MAPK pathway signaling. Then, the C-terminus of the inherent Gpa1 of S. cerevisiae was replaced with the five residues of human taste converting protein so that Gpa1 could interact with T1R2/T1R3 for sweetness signaling. Finally, the human sweetness receptor T1R2/T1R3 was heterologously expressed in engineered S. cerevisiae by N-terminal signal peptide engineering, creating strain D3Gm, which showed the ability to sense sweeteners. This study provided proof of the concept that S. cerevisiae can be engineered to sense sweetness.