1. Department of Chemistry University of Natural Resources and Life Sciences-Vienna Muthgasse 18, Wien A-1190 Vienna Austria
2. Faculty of Health Sciences and Department of Molecular Biology & Biochemistry Simon Fraser University Burnaby British Columbia V5A1S6 Canada
3. Present address: CIRI-Centre International de Recherche en Infectiologie University of Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon 46 Allée d'Italie 69007 Lyon France