So remember, the end domain binds that ATP nucleotide to this section. And so now we go from this stage to the e one calcium to ATP stage. And as soon as the ATP binds onto this green section, it creates a localized conformational change in the green structure, the blue structure, and this purple structure. And what that does is it seals off, it blocks off this entrance here and also exits. And so now these calcium ions are trapped inside this pocket, inside that transmembrane domain. Now, notice this transmembrane domain didn't actually undergo a conformational change.