1. Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77843-3012, United States
2. Department
of Biochemistry, Einstein College of Medicine, Bronx, New York 10461, United States
3. Department
of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
4. Biology
Department, Brookhaven National Laboratory, P.O. Box 5000, Upton, New
York 11973-5000, United States