1. Department
of Biochemistry, Stanford University, B400 Beckman Center, 279 Campus
Drive, Stanford, California 94305, United States
2. Department
of Chemistry, Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
3. Stanford
Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
4. Department
of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305, United States
5. Department
of Chemistry, University of Illinois at Urbana-Champaign, 600
South Mathews Avenue, Urbana, Illinois 61801, United States