1. Department of Chemical Engineering and Applied Chemistry University of Toronto ON M5S 3E5 Canada
2. Structural Biology Center Argonne National Laboratory Argonne IL 60439 USA
3. Centre for Structural and Functional Genomics Concordia University Montreal QC H4B 1R6 Canada
4. Department of Chemistry and Biochemistry Concordia University Montreal QC H4B 1R6 Canada
5. Department of Biology Concordia University Montreal QC H4B 1R6 Canada