1. Department
of Experimental Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
2. Department
of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse
2, D-12489 Berlin, Germany
3. Molecular Biology Institute of Barcelona (IBMB−CSIC), Barcelona Science Park, c/Baldiri Reixac 15, 08028 Barcelona, Spain
4. Laboratory
of Crystallography, BGI-building, Universität Bayreuth, Universitätsstrasse
30, D-95447 Bayreuth, Germany