Interaction between Sweet Taste Receptor and Sweet-Tasting Proteins by using Molecular Dynamics Simulation

The human sweet taste receptor (hT1R2-hT1R3) is the heteromeric complex composed of hT1R2 and hT1R3 subunits belonging to the class C G-protein-coupled receptors (GPCRs). The crystal structure of hT1R2-hT1R3 is not available in nowadays, so homology modeling was applied to model the hT1R2-hT1R3. The hT1R2-hT1R3 can bind with a wide variety of chemical substances including naturally occurring sugars, D-amino acids, as well as artificial chemical compounds. Moreover, naturally sweet-taste proteins, such as brazzein also bind to hT1R2–hT1R3 but the interaction remains unclear. In this study, brazzein was docking to the 2 forms of hT1R2-hT1R3, which are closed-hT1R2/open-hT1R3 and open-hT1R2/closed-hT1R3. The molecular dynamics simulation and intermolecular interactions between proteins suggested that brazzein preferred to bind with the open form subunit of closed-hT1R2/open-hT1R3 rather than open-hT1R2/closed-hT1R3. These results could provide a more understanding of interaction between human sweet taste receptor and brazzein.