1. Department of Molecular Biophysics and Biochemistry, Yale University, New Haven Connecticut 06520, United States
2. Department of Chemistry, Yale University, New Haven Connecticut 06520, United States
3. Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, United States
4. Department of Chemistry, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, United States
5. Department of Biology, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, United States
6. Fellow, Bio-inspired Solar Energy Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON M5G 1M1, Canada