1. Department
of Chemistry, Syracuse University, 111 College Place, Syracuse, New York 13244, United States
2. Department
of Pharmaceutical Chemistry, University of California—San Francisco, 555 Mission Bay Boulevard South, San Francisco, California 94158, United States
3. Jean
Jeener NMR Centre, Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium