Hi, everyone,
I am recently solving a structure at 1.8A. After I fitted all residues into the model, I found that there was an extra density in a pocket consisted of E, N, R and other hydrophobic residues. The density is strong and connected like a butterfly. I checked the crystallization condition. I can not figure out what it is. It seems that it is not from the crystallization components. Does anyone know how to figure out what the density is? Is there any program or database I can use to predict the potential ligand? Thanks. Mousheng