So these two dimers basically begin to rotate 50 degree, 15 degrees with respect to one another. And that conformational change basically collapses this inner pocket, and it squeezes the two three BPG molecule right out of the center of the hemoglobin. And once the two three BPG is squeezed out of that pocket, that shifts our equilibrium back to the right side, the r state. And that makes the heme groups much more likely to bind oxygen. And that's a very important idea, because when the deoxyhemoglobin returns back to the lungs, we want that hemoglobin to be able to easily bind to oxygen with a high affinity. And that's exactly what we see actually happen.