1. Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt am Main D-60438, Germany
2. Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Frankfurt am Main D-60438, Germany
3. Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main D-60438, Germany
4. Redox and Metalloprotein Research Group, Max Planck Institute of Biophysics, Frankfurt am Main D-60438, Germany
5. Max Planck Institute for Terrestrial Microbiology, Marburg D-35043, Germany
6. Max Planck Institute for Marine Microbiology, Bremen D-28359, Germany