I have a PDB file with the following: MODEL1 = Receptor (chain A)+ Mg (chain A) and MODEL 2 = ATP molecule (chain B). Should I transform this PDB file to contain only one model (RECEPTOR (chain A) + Mg (chain A) + ATP (chain A)) or can I run DelPhi this way? Merging the structures results an error ("midpoint out of cube"); If I maintain as separate models, it runs.