1. Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet – Biomedicum, Solnavägen 9, 17165 Solna, Sweden
2. Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark
3. Department of Chemistry and Biochemistry, University of Arizona, Marvel Hall 542, Tucson, AZ 85721, U.S.A
4. Bio5 Institute, University of Arizona, Marvel Hall 542, Tucson, AZ 85721, U.S.A