1. Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine , St. Louis , MO 63104 , USA
2. Department of Chemistry, Science Institute, University of Iceland , 107 Reykjavik , Iceland
3. Department of Biochemistry and Molecular Biophysics, Washington University in Saint Louis School of Medicine , St. Louis , MO 63110 , USA
4. Department of Chemical and Structural Biology, Weizmann Institute of Science , Rehovot , Israel
5. Department of Chemistry and Biochemistry, Montana State University , Bozeman , MT 59717, USA
6. Department of Biochemistry and Biophysics, Oregon State University , Corvallis , OR 97331 , USA
7. Department of Biology, Saint Louis University , St. Louis , MO 63103 , USA