If you have two protein structures with the same atom namse and ALTER records but with different conformations you can impose the conformation of one of the protein structures onto the other.

You can do this by:

• Convert the structures into ICM Objects.
• MolMechanics/Impose Conformation
• Select the source molecule (the conformation you wish to impose).
• Optional: superimpose the structures
• Optional: re-optimize hydrogens