1. Department of Chemistry William & Mary Williamsburg VA 23185 USA
2. Medical School, Institute of Biochemistry II Structural Bioenergetics Group Goethe University 60590 Frankfurt am Main Germany
3. Centre for Biomolecular Magnetic Resonance Institute for Biophysical Chemistry Goethe University 60438 Frankfurt am Main Germany
4. Institute of Pharmaceutical Biology Goethe University 60438 Frankfurt am Main Germany
5. Department of Cellular Microbiology University Hohenheim 70599 Stuttgart Germany
6. Department of Biological Sciences Illinois Institute of Technology Chicago IL 60616 USA