1. Department of Analytical Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic, Department of Chemistry and Biochemistry and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712-1167, Institute of Molecular Genetics, Academy of Sciences of Czech Republic, Flemingovo sq. 2, 16610 Prague, Czech Republic, and Institute of Biophysics, First Medical Faculty of Charles University, Salmovská 1 Prague, Czech Republic