1. Department of Biophysics; Ruhr University Bochum, Universitätsstr. 150; Bochum D-44801 Germany
2. Institute for Molecular Microbiology and Biotechnology; University of Münster; Germany
3. Microbial Biology, Ruhr University Bochum, Universitätsstr. 150; Bochum D-44801 Germany
4. Medizinisches Proteom-Center, Ruhr-University Bochum, Universitätsstr. 150; Bochum D-44801 Germany