Most options work just as well with proteins as with any other type of molecule.

• Refi_zone - needs a separate dictionary
• Rsr_* works on anything that you specify as having fragments (rsr_zone) or as a rigid body.
• The Lego_* functions don't map well to nucleic acids; they are too floppy for the main chain db.

According to Alwyn (931103): "I'm certainly not happy with O's handling of non-amino acids and would be willing to add new commands to make things easier. For example, I thought it might be useful to have a command that placed a residue at the screen centre in some standard conformation. For nucleic acids you would have to have in your database a set of mini-molecules (just like we have alpha helices etc). Then you could fit it the usual way, with move_zone, torsion, rsr, refi etc."