And this is known as the f kno region. And the f knot region actually contains that proton channel that rotates. And we'll talk about that much more detail in the next lecture. In this lecture I'd like to focus on the other region, the f one region because it's the f one region that contains the catalytic structure. The catalytic structure is known as the alpha three beta three hexamurine. So the f one region of ATP synthase contains that hexamurine, the alpha three beta three structure that actually catalyzes the formation of ATP molecules.