Phil, > If I "colour by chain" (my preferred option), metal ions disappear I see, but not all metals disappear (only your favourite ones I guess, e.g. PT is there). Not sure if feature or bug (I guess the latter). > also is there any way of refining a zone around a metal ion without the sidechains vanishing into the metal density? I know the refine-by-sphere ("R") option works better, but then I have no control over what I'm refining There are two ways how to do this: - mask your map (Extensions->Maps->Mask Map by Atom Selection) - define your own residues to be included in the refinement (as done in sphere_refinement, i.e refine_residues; see e.g. fitting.py) I can elaborate more on these if needed. Hope this helps, B -- *************************************************** Dr. Bernhard Lohkamp Assistant Professor Div. Molecular Structural Biology Dept. of Medical Biochemistry and Biophysics (MBB) Karolinska Institutet S-17177 Stockholm Sweden phone: (+46) 08-52487651 fax: (+46) 08-327626 email: [log in to unmask]