1. Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
2. Department of Pharmacy, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
3. Department of Chemistry, New York University, New York, New York 10003, United States
4. Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720, United States
5. Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States