1. Department of Molecular Biology, Skaggs Institute for Chemical Biology, Consortium for Functional and Structural Proteomics of the SARS-CoV, and Joint Center for Structural Genomics, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
2. Institut für Molekularbiologie und Biophysik, ETH Zürich, CH-8093 Zürich, Switzerland