1. Department of Life Technologies, University of Turku, FIN-20014 Turku, Finland
2. Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden
3. Department of Chemistry, University of Turku, FIN-20014 Turku, Finland
4. Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden