And by binding to the C Five protein, it basically creates a conformational change and it prepares it for cleavage by the C four B C two B complex. Remember, this complex doesn't only activate C three, it also activates C Five. So we have this very complex mechanism where many different proteins activate other proteins. And that's why we call this a cascade of events. In fact, the complement system is also sometimes known as the complement cascade system because we have so many events taking place and so many proteins are being activated. So let's see exactly how the C Five is activated.