Now, once we hydrolyze the ATP into ADP and the phosphate and once the calcium binds onto our troponin exposing that binding site, now the binding can actually take place. So now the myosin head is oriented correctly. So what also happens when we have our hydrolysis is in this diagram, the myosin head is oriented at a 45 degree angle with respect to our thick filament. But when we have hydrolysis taking place, when we produce the ADP and the P, this myosin head orients itself approximately at a 90 degree angle with respect to our thick filament as shown in this diagram. And now the orientation is just right for this mice and head to actually bind to our binding side as shown in this diagram. And this binding, let's label this as step number four.