1. Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA.
2. Institute of Biochemistry, Albert-Ludwigs Universität, Freiburg, Germany.
3. Biochemistry Department, Virginia Tech, Blacksburg, VA 24061, USA.
4. Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany.
5. Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
6. Department of Chemistry, Yale University, New Haven, CT 06520, USA.
7. Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA.