Institution: | a Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA b Molecular Bioenergetics Group, Cluster of Excellence Frankfurt “Macromolecular Complexes”, Medical School, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany c Institut für Physikalische und Theoretische Chemie, Johann Wolfgang Goethe-Universität Frankfurt, D-60439 Frankfurt am Main, Germany |