1. Department
of Biochemistry, University of Vermont, College of Medicine, 89 Beaumont
Avenue, Burlington, Vermont 05405, United States
2. Department of Chemistry, Parsons
Hall, University of New Hampshire, Durham,
New Hampshire 03824, United States
3. Department of Biochemistry and
Molecular Biology and Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada