Because gustducin had been previously shown to coordinate bitter responses to certain tastants, the authors suggested that gustducin may couple with a protein implicated in the bitter response. They then went on to show that both gustducin and T2R are expressed in similar regions in the oral cavity. The genes were identified by monitoring conserved sequences in individuals who did not exhibit a strong bitter response. The predicted amino acid sequences are shown for the genes that have been predicted to be involved bitter perception. The sequence regions where at least half of the amino acids are identical are shaded darkly.
Gray areas indicate conservative amino acid substitutions.
The sequences are from different T2R taste receptors in human, mouse and rat. An abundance of predicted protein sequences are listed for human and rat. Only ten T2R protein sequences have been predicted for mouse. Predicted transmembrane domains are indicated by solid bars above the protein sequences. Seven transmembrane domains have been predicted for this class of T2R proteins.