1. Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
2. Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
3. Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
4. Department of Microbiology, University of Washington, Seattle, Washington, USA
5. Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
6. Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA