1. Department of Bioengineering, Stanford University, Stanford, California 94305, United States
2. Department of Neurobiology, Stanford University, Stanford, California 94305, United States
3. Promega Biosciences LLC, San Luis Obispo, California 93401, United States
4. Department of Chemistry, Aarhus University, Aarhus 8000, Denmark
5. Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305, United States
6. Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, United States
7. Department of Pediatrics, Stanford University, Stanford, California 94305, United States
8. Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States