1. Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
2. Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
3. Basilea Pharmaceutica International Ltd., Grenzacherstrasse 487, CH-4058, Basel, Switzerland