And so the partially negative oxygen of these water molecules will form bonds, coordinate bonds with this magnesium atom and this will stabilize that structure and create a conformational change that will basically bridge that active side structure and the structure of this particular substrate molecule. So the magnesium will interact with two oxygen atoms on the ATP molecule as well as four water molecules and the interaction will hold that substrate in a well defined conformation, a well defined shape that is suitable for the shape of the active side found in that enzyme. And so ultimately, we see that the metal ion serves as a bridge between the substrate molecule and the enzyme. Without that metal ion the substrate would not be able to bind into the active side because it would not have the proper orientation. And so ultimately, it's the ATP metal ion complex that is the substrate of that active side because only when the metal atom binds with the ATP molecule will the interactions between the active side and the substrate be perfect and very stabilizing interactions. Now, the final thing that I'd like to mention about MP kinases is that they not only use the metal ion catalysis, but they also use catalysis by proximity and orientation.