1. Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, HR-10000 Zagreb, Croatia, Ruđer Bošković Institute, Division of Organic Chemisty and Biochemistry, Laboratory of Supramolecular and Nucleoside Chemistry, P. O. Box 180, HR-10002 Zagreb, Croatia, and Ruđer Bošković Institute, Division of Molecular Medicine, Laboratory of Functional Genomics, P. O. Box 180, HR-10002 Zagreb, Croatia