I need some help getting started with this question. I have identified the crystal structures but I'm not sure what is attacking first?

8. Now that you have a basic understanding about how enzymes can catalyze chemical transformations, you know enough to propose mechanisms for enzyme-catalyzed reactions that you have not formally studied! Below is shown the crystal structure for an unknown enzyme, complete with relevant amino acid residues and the substrate. Red = oxygen Blue = nitrogen Lime green = chlorine Dark green = carbon Asp N His The overall reaction catalyzed by this enzyme is as follows: Enzyme CI CI H20 HO a) Mechanistic studies have shown that this enzyme first forms an acyl enzyme intermediate before water is permitted to enter the active site. With this information in mind, think carefully about the possible roles of each of the amino acid residues shown in the active site. Then propose a complete curved-arrow mechanism that is consistent with the provided information. Do not include any active site components that are not shown in the crystal structure above. You may invoke general acids or bases if necessary