1. Microbiology Department, Pav. Charles-Eugene Marchand, Université Laval; Quebec G1K 7P4 Canada
2. Physics Department, University of Waterloo; Waterloo Ontario N2L 3G1 Canada
3. Chemistry Department, Brookhaven National Laboratory; Upton NY 11973 USA
4. Molecular Biology Department, The Scripps Research Institute; 10550 North Torrey Pines Road La Jolla CA 92037 USA
5. Biochemistry Department, Imperial College; London SW7 2AZ UK