Wouldn't - in the case of non-isomorphsim - a molecular replacement with the apo-form come closest to a Fo(complex)-Fo(apo) map?I know that sometimes Fo(complex)-Fo(apo) cannot be done because of nonisomorphism. We've had a lot of success with this with the dioxygenases because there is no large scale alteration in the active site. As for the technique itself, Brian Matthews drilled this into me when I was a postdoc in his lab.
Just a thought. Tim
