Now, before the binding takes place, we see that this g protein contains the GDP guanosine diphosphate bound to it. And what that means is the affinity of the g alpha Q protein for these two domains is very high. And so it will exist in this trimeric form and it would be bound to that seven transmembrane helix structure shown in green. But when the binding process takes place so let's imagine this is the angiotensin two receptor. In that case, the primary messenger is angiotensin, the peptide hormone. When that peptide hormone binds onto this site here, that creates a conformational change in the structure of the green piece and then that induces a change in this orange piece.