1. Rosalind Russell Medical Research Center, Departments of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California 94143-0703
2. Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, 1000 Ljubljana, Slovenia
3. Institute of Biochemistry, Medical Faculty of the University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia