1. Department of Biochemistry, University of Montreal, P.O. Box 6128, Station “A” Montreal, Quebec, Canada H3C 3J7
2. Universitá Rená Descartes, UFR des Sciences Pharmaceutiques et Biologiques, Dápartement de Chimie Organique, U266 INSERM-URA498 CNRS, 4 Avenue de l'Observatoire, 75270 Paris Cedex 06, France