1. Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada, K1H 8M5.
2. Department of Chemistry, Carleton University, Ottawa, Ontario, Canada, K1S 5B6.
3. Corresponding author. Phone: (613) 562-5800, ext. 6374. Fax: (613) 562-5452. E-mail: altosaar@uottawa.ca