1. Department of Physics, Chalmers University of Technology, Fysikgränd 3, 412 96 Göteborg, Sweden
2. Department of Infectious Diseases, Section for Clinical Virology, Institute of Biomedicine, University of Gothenburg, Guldhedsgatan 10B, 413 46 Göteborg, Sweden
3. Department of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 3, 141 95 Berlin, Germany
4. Wallenberg Centre for Molecular Medicine and Department of Clinical Microbiology, Umeå University, NUS Målpunkt R, 901 85 Umeå, Sweden