So let's focus on how this actually takes place inside the active side of this transpeptidase enzyme. So this is a portion of the active side and this is that catalytic residue, that Serene molecule. So what happens is we take this blue molecule that we have here that is basically attached to, let's say, the linear polysaccharide chain here. And what happens is this Serene molecule, the oxygen, basically binds onto this carbon and that kicks off this first dalanine to basically form the astle intermediate as well as this individual D. Alanine that was removed. And now what happened is we basically prepare this section here. So this molecule here to form that cross linkage between this carbon here and this nitrogen here.