1. Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
2. Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
3. Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
4. Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
5. Max Planck Institute for the Structure and Dynamics of Matter, Atomically Resolved Dynamics Division, Building 99 (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
6. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
7. Department of Biotechnology, Chemistry and Pharmacology, Universitá di Siena, via De Gasperi 2, I-53100Siena, Italy