1. Department of Biochemistry, McGill University, 3655 Drummond Street, Montreal, Quebec, Canada, H3G 1Y6.
2. Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Post Office Box 1005, Pointe Claire-Dorval, Quebec, Canada, H9R 4P8.
3. Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada, K1H 8M5.