1. Department of Biochemistry, 561 Medical Sciences Building, University of Alberta, Edmonton, AB, T6G 2H7, Canada
2. The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037 U.S.A.
3. Institute for Biomolecular Design, 367 Medical Sciences Building, University of Alberta, Edmonton AB, T6G 2H7, Canada