1. Bio-organic Synthesis; Leiden University; Einsteinweg 55, 2333 CC Leiden The Netherlands
2. Current address: ProQR Therapeutics; Leiden The Netherlands
3. Institute of Biochemistry II; Goethe University Faculty of Medicine; Theodor-Stern-Kai 7 60590 Frankfurt am Main Germany
4. Buchmann Institute for Molecular Life Sciences; Goethe University Frankfurt, Riedberg Campus; Max-von-Laue-Straße 15 60438 Frankfurt am Main Germany
5. Department of Chemical Immunology; Leiden University Medical Centre; Einthovenweg 20 2333 ZC Leiden The Netherlands