1. Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
2. National Institute of Mental Health Psychoactive Drug Screening Program, Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, NC 27599, USA.
3. Van Andel Research Institute/Shanghai Institute of Materia Medica Center, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
4. Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA.