1. Department of Molecular Biology; The Scripps Research Institute; La Jolla; California; 92037
2. Department of Chemistry and Chemical Biology; Northeastern University; Boston; Massachusetts; 02115
3. Departamento de Química Orgánica, Laboratorio de Investigación Ignacio Ribas; Universidad de Santiago de Compostela; E-15706; Santiago de Compostela; Spain
4. Institute for Theoretical Chemistry; University of Vienna; Vienna; Austria
5. Epimer LLC; North Smithfield; Rhode Island; 02896