I have fixed the bugs in PE 2.721 that prevented Presentations in Protein Explorer from working on Macs. The new version of PE is dubbed PE 2.721mac. It is available on-line at proteinexplorer.org, and can be downloaded. Windows users can continue to use downloaded copies of 2.721, and 2.721mac works fine on-line on both Macs and Windows. -Eric ---- Eric Martz, Professor Emeritus, Dept Microbiology University of Massachusetts, Amherst MA US http://www.umass.edu/molvis/martz