1. Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
2. Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
3. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 20139, United States
4. Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 20139, United States
5. Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 20139, United States
6. Fellow, Bio-inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1M1, Canada