1. Department of Bio-organic Synthesis Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands
2. Department of Medical Biochemistry Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands
3. Biomedical Sciences Research Complex School of Biology University of St Andrews North Haugh St Andrews Fife KY16 9ST UK
4. Department of Biological Sciences Simon Fraser University 8888 University Drive Burnaby BC V5A 1S6 Canada