I'm new to Chimera and trying to create a figure panel for a paper. I'm running Chimera on a Mac from the graphical interface. The protein is a a yeast topoisomerase II. Its PDB ID is 2RGR. If I view the protein with Cn3D I can see the whole biological unit, in which the protein is present as a symmetrical dimer (with some DNA strands too). If I view it with Chimera I see a protein monomer. The problem is I want to illustrate a particular intermolecular salt bridge, which is present in the dimer but isn't present in the monomer. Is there some preference to toggle to allow Chimera to display the whole biological unit? Or would I have to artificially build a dimer out of two monomer models? Thanks, Jim -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- James E. Ferrell, Jr., M.D., Ph.D. Professor and Chair of Chemical and Systems Biology Stanford University School of Medicine